A 0.18 μm CMOS linear-in-dB AGC post-amplifier for optical communications

This paper presents a fully integrated 10GBase-LX4 Ethernet receiver front-end automatic gain control amplifier realized in a 0.18 μm CMOS process. Based on a very compact and reliable inductorless design, the proposed differential post-amplifier, comprises three main digitally programmable gain stages, a DC offset cancellation network and an automatic gain feedback control loop. Experimental results demonstrate a −3 dB cut-off frequency above 2.3 GHz over a −3 to 33 dB linear-in-dB controlled gain range with a sensitivity of 2.0 mV_p-p with a BER of 10⁻¹² at 2.5 Gb/s. For the aforementioned standard, 3.125 Gb/s, an input dynamic range above 50 dB is achieved, from 2.5 mV_p-p to 800 mV_p-p, indicating a BER of 10⁻¹². The chip core area is 0.3 × 0.3 mm² and it consumes 58 mW with a single supply voltage of 1.8 V.     

Network positioning and risk perception in servitization: evidence from the UK road transport industry

For manufacturing firms, the integration of advanced services into their customer offerings has become a crucial decision. Such commercial decisions require weighting the risks and rewards of implementing a business model based on advanced services. While academic experts acknowledge uncertainty of returns on investment despite potential advantages, research generally fails to address the challenge of calculating the actual risks involved in ‘servitization’. This paper seeks better understanding of managers’ risk perception and of servitization implications for strategic partnerships and network positioning, while considering the impact of factors such as entry barriers, technological knowledge and position in the supply chain (SC). Qualitative evidence is drawn from an industrial case study involving firms in the UK’s road transport industry: 14 in-depth interviews with senior executives from seven companies (manufacturers, operators, technology providers). During interviews, a payment card exercise measured risk perception and willingness to take strategic ‘make-or-buy’ decisions. Results suggest that implementing advanced services is perceived as a high-risk strategy, especially when firms lack in-house technological knowledge. However, collaborative strategic partnerships within supply chain networks can mitigate this risk and prove crucial to building entry barriers against external competitors. Based on these findings, implications for network positioning are developed.     

Thin-layer drying behaviour of sludge of olive oil extraction

Drying characteristics of sludge were examined for average moisture content from 2 to approximately 0.7–0.08 kg water/kg dry matter using hot air of the range of 20–40–80 °C and simulating the interval that can be provided by an air solar heater and by air velocities of 1 m/s at a laboratory scale dryer. Different mathematical models were used for the simulation of the sludge drying curves, such as Lewis, Page, Modified Page, Henderson and Pabis, Wang and Singh, Logarithmic, Two term, Two Term exponential, Modified Henderson and Pabis, Midilli, Approximation of diffusion, Verma et al. and Simplified Fick’s diffusion models. The performance of these models was investigated by comparing four statistical parameters: the square of the coefficient of determination (r²), reduced chi-square (χ²), root mean square error (RMSE) and sum of residuals between the observed and predicted moisture ratio. The Midilli model represented the drying characteristics better than the others. The effective diffusivity coefficient of moisture transfer varied from 2.224 × 10⁻¹⁰ to 6.993 × 10⁻¹⁰ m²/s over the temperature range. The temperature dependence of the effective diffusivity coefficient was expressed by Arrhenius type relationship. The activation energy for the moisture diffusion was found to be 15.77 kJ/mol.     

Prenatal exposure to mercury in a prospective mother-infant cohort study in a Mediterranean area, Valencia, Spain

BACKGROUND: Mercury (Hg) is a ubiquitous pollutant that negatively affects fetal and child neurodevelopment at accidental high-dose exposure. Some studies indicate that Mediterranean populations could be at risk of prenatal exposure to mercury through fish consumption. OBJECTIVES: To assess the prenatal exposure to total mercury (T-Hg), both inorganic and organic, in newborns by analyzing the T-Hg concentration in cord blood, and to evaluate the role of maternal fish consumption in this exposure. METHODS: In the context of a multi-center project (INMA project), a prospective birth cohort was set up in Valencia, Spain, from 2005 to 2006. A total of 253 newborns were included in this study. We compared cord blood T-Hg concentration by levels of fish intake assessed by a food frequency questionnaire completed at 28-32 weeks of gestation. Maternal covariates were obtained through a questionnaire. RESULTS: The geometric mean of T-Hg at birth was 9.9 microg/L (95% CI: 9.0, 10.8). Seventy five percent of cord blood samples were above the estimated level assumed to be without appreciable harm (5.8 microg/L). Women who consumed a portion of large oily fish, lean fish, or mixed fried fish two or more times per week had mean cord blood levels 1.6, 1.4 and 1.3 times higher, respectively, than those who rarely or never consumed fish. Other factors such as the mother's age, country of origin, smoking and season of delivery were also significantly and independently associated with cord blood T-Hg concentrations. CONCLUSIONS: Newborns from a Mediterranean area presented elevated levels of T-Hg in cord blood. Higher concentrations of T-Hg were related to maternal fish intake, particularly in the case of large oily fish species.     

A multiplier evaluation of primary factors supply–shocks in a regional economy

Demand-side multipliers have ruled within multisectorial models as the main indicators for policy effectiveness and key-sector determination both in linear interindustry analysis and in non-linear applied general equilibrium models. In this paper we shift the perspective to supply-side injections by studying the effects of marshalling additional primary factors (K, L) that give rise to a general resource reallocation. We obtain estimates of supply multipliers by numerically approximating the underlying and unobservable general equilibrium Jacobian matrix. These estimates provide complementary information to standard demand multipliers. We illustrate the methodology using an empirical general equilibrium model for the region of Andalusia, Spain.     

Spanish sentiment analysis in Twitter at the TASS workshop

This paper describes a support vector machine-based approach to different tasks related to sentiment analysis in Twitter for Spanish. We focus on parameter optimization of the models and the combination of several models by means of voting techniques. We evaluate the proposed approach in all the tasks that were defined in the five editions of the TASS workshop, between 2012 and 2016. TASS has become a framework for sentiment analysis tasks that are focused on the Spanish language. We describe our participation in this competition and the results achieved, and then we provide an analysis of and comparison with the best approaches of the teams who participated in all the tasks defined in the TASS workshops. To our knowledge, our results exceed those published to date in the sentiment analysis tasks of the TASS workshops.     

Prenatal exposure to lead in Spain: cord blood levels and associated factors

Introduction and Objective

Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood).

Methods

A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2 μg/dL).

Results

A low percentage of cord blood samples with lead levels ≥ 2 μg/dL were found (5.9%). Geometric mean and maximum were 1.06 μg/dL and 19 μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2 μg/dL.

Conclusion

In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels.     

The homogeneity ranges of the L12-type intermetallic compounds Ni3Ga and Ni3Ge

The homogeneity ranges of the L1₂-ordered compounds Ni₃Ga and Ni₃Ge and the boundaries of the neighboring phases have been examined by electron probe microanalysis using heterophase alloys in the temperature ranges 1073 to 1373 K (Ni-Ga) and 1073 to 1346 K (Ni-Ge). The composition ranges of the L1₂-ordered phases have been found to be narrower than those reported in the literature, on the Ga-rich side for Ni₃Ga and on the Ge-deficient side for Ni₃Ge.     

Experimental modelling of infrared drying of industrial grape by-products

The thin-layer infrared drying behaviour of industrial grape by-products was experimentally investigated in the temperature range from 100 to 160 °C. The drying rate was found to increase with temperature, thus reducing the total drying time. In particular, as drying temperature was raised from 100 °C up to 160 °C, the time period needed to reduce the moisture content of the sample from 204.32% down to 38.89% by weight (dry basis) decreased from 60.5 to 21 min.Using a non-linear regression (Marquart's method) together with a multiple regression analysis, a mathematical model for the thin-layer infrared drying process of wet grape residues was proposed. The values for the diffusivity coefficients at each temperature were obtained using Fick's second law of diffusion. They varied from 11.013 × 10^?9 to 26.050 × 10^?9 m²/s along the temperature range. The temperature dependence of the effective diffusivity coefficient was expressed by an Arrhenius type relationship. Activation energy for the moisture diffusion was determined as 19.27 kJ/mol.     

Long-term in vivo left ventricular assist device study with a titanium centrifugal pump

A totally implantable centrifugal artificial heart has been developed. The plastic prototype, Gyro PI 601, passed 2 day hemodynamic tests as a functional total artificial heart, 2 week screening tests for antithrombogenicity, and 1 month system feasibility. Based on these results, a metallic prototype, Gyro PI 702, was subjected to in vivo left ventricular assist device (LVAD) studies. The pump system employed the Gyro PI 702, which has the same inner dimensions and the same characteristics as the Gyro PI 601, including an eccentric inlet port, a double pivot bearing system, and a magnet coupling system. The PI 702 is driven with the Vienna DC brushless motor actuator. For the in vivo LVAD study, the pump actuator package was implanted in the preperitoneal space in two calves, from the left ventricular apex to the descending aorta. Case 1 achieved greater than 9 month survival without any complications, at an average flow rate of 6.6 L/min with 10.2 W input power. Case 2 was killed early due to the excessive growth of the calf, which caused functional obstruction of the inlet port. There was no blood clot inside the pump. During these periods, neither case exhibited any physiologic abnormalities. The PI 702 pump gives excellent results as a long-term implantable LVAD.