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An event-based modification of the classical relay feedback experiment without the inclusion of additional elements (integrator, time delay, ...) for identification of the spectrum of stable processes between zero and the phase cross-over frequency is presented. By inserting an event-based sampler in the control loop, the natural behaviour of a classical relay is simulated and the system is forced to work in two modes. The event-based sampler activates the first mode by sending control actions to the process every time the error signal crosses zero; this mode is to discover the approximated value of the cross-over frequency ω 18 0 ∘ . During the second mode, the event-based sampler sends samples to the process simulating that the error signal crosses zero at ω 18 0 ∘ / N where N is the number of points to identify in the range 0 ≤ ω ≤ ω 18 0 ∘ . One advantage of this procedure is that the logic used in an already existing relay feedback experiment to fit a transfer function model or tune a controller could be maintained just replacing the relay block by the event-based sampler block presented in the paper. Simulations and experiments with different processes and in presence of noise demonstrate the effectivity of the procedure. • Identification of stable processes between zero and the phase cross-over frequency. • Event-based modification of the classical relay feedback experiment. • Overcomes some of the limitations of the relay feedback method. • Can identify the steady gain and low-frequency points of the spectrum. • Simulations and experiments demonstrate effectivity in processes with noise. [ABSTRACT FROM AUTHOR]

Hirschsprung disease affects many children every year around the world. Currently, there is an extensive menu of diagnostic methods, and surgical treatments. This situation compels the physicians to follow the rationale of these interventions. The comprehensive diagnosis and treatment of Hirschsprung disease need singular procedures. The clear understanding of how to perform each of these techniques, as well as to read the results is mandatory. Otherwise, the medical team may perform unconscious errors and fall into traps. Many errors still happen in patients with Hirschsprung, resulting in a spectrum of problems; from delayed diagnosis to unnecessary colectomies. In other patients, the damage to the anal canal results in fecal incontinence. When this is established, it is an unreversed and devastating social problem. This article describes why these errors occur and how to prevent them. [ABSTRACT FROM AUTHOR]

The Atacama desert is a region with exceptional conditions for solar power production. However, despite its relevance, the impact of climate change on this resource in this region has barely been studied. Here, we use regional climate models to explore how climate change will affect the photovoltaic solar power resource per square meter (P V r e s ) in Atacama. Models project average reductions in P V r e s of 1.5% and 1.7% under an RCP8.5 scenario, respectively, for 2021-2040 and 2041-2060. Under RCP2.6 and the same periods, reductions range between 1.2% and 0.5%. Also, we study the contribution to future changes in P V r e s of the downwelling shortwave radiation, air temperature and wind velocity. We find that the contribution from changes in wind velocity is negligible. Future changes of downwelling shortwave radiation, under the RCP8.5 scenario, cause up to 87% of the decrease of P V r e s for 2021-2040 and 84% for 2041-2060. Rising temperatures due to climate change are responsible for drops in P V r e s ranging between 13%–19% under RCP2.6 and 14%–16% under RCP8.5. We conclude that climate change has the potential to impact the P V r e s in the Atacama region while retaining exceptional conditions for solar power production. [ABSTRACT FROM AUTHOR]

This paper reports the study of different aspects of data based modelling, focusing on physical issues and considering a simplified case study. Different analysis approaches have been applied to several data series recorded in different test conditions. The results have been compared. The effect of solar radiation, and the relevance of non- constant surface effects have been evaluated through an exploratory mono-dimensional analysis. Afterwards tri- dimensional analysis has been applied, to estimate the overall UA and gA value of the simplified building. The robustness of the results is studied comparing results from data set recorded under different test conditions. [ABSTRACT FROM AUTHOR]

Abstract: It has been demonstrated that the spatial structure of the Northern Annular Mode depends on external forcings such as solar activity. In some cases, this variations lead to a spatial pattern very similar to that of the so-called North Atlantic Oscillation. In this work, we use relative angular momentum, trying to provide more information about this solar effects and how they affect this variability pattern. An analysis about a possible modulation of the QBO is also included. [Copyright &y& Elsevier]

The nitrogen doped carbon nanotubes present specific characteristics that offer better performance than pure carbon nanotubes for application like biomedicine, hydrogen adsorption and electrocataytic devices. This work present a simple method to obtain well-aligned nitrogen doped multi wall carbon nanotubes, which present open channels with diameter around 50 nm. These carbon nanotubes are obtained using acrylonitrile as carbon and nitrogen source, which offers some advantages on the use of other precursors like ammonia, pyridine, benzylamine, acetonitrile or melamine. [ABSTRACT FROM AUTHOR]

OBJECTIVES: This study was undertaken to determine risk factors and perioperative complications associated with accidental extensions in the lower uterine segment during cesarean deliveries (CDs). STUDY DESIGN: This is a retrospective chart review of all CDs performed at Jackson Memorial Hospital/University of Miami between the years 1999 and 2002. Operative reports were reviewed to abstract data on the occurrence of extensions. Indication for CD, cervical status at the time of CD, birth weight, and fetal presentation and position were included in the analyses. Postoperative hematocrits, length of surgery, estimated blood loss, decline in hematocrit by 10%, need for transfusion, or hysterectomy were compared among CD with and without extensions. RESULTS: A total of 2,811 CDs were available for this study. Accidental extensions in the lower uterine segment occurred in 6.6% of the cases. Extensions were more commonly found in primary CD (8% vs 5%, P < .01. Extensions were more frequent if cervical dilatation was 8 cm or greater (18.3% vs 7%, P < .01), complete effacement (15% vs 8%, P < .01) station greater than +1 (16% vs 6.9%, P < .01), and if the fetal position was noted to be in the occiput posterior position (10% vs 5%, P < .01). When extensions were present, length of surgery was longer (56 vs 49 minutes, P < .01) and estimated blood loss was greater (994 +/- 675 mL vs 936 +/- 370 mL, P < .01). Arrest of descent as indication for CD was found to be an independent risk factor for the occurrence of extensions during CD (odds ratio 2.6, 95% CI 1.5-4.5, P = .001). CONCLUSION: Extensions in the lower uterine segment during CD do not increase maternal morbidity. [ABSTRACT FROM AUTHOR]

Abstract: The inbred Roman High- (RHA-I) and Roman Low-Avoidance (RLA-I) rats, psychogenetically selected for rapid (RHA-I) vs. extremely poor (RLA-I) acquisition of two-way active avoidance, exhibit a lower or a higher level of fearfulness, respectively, that can be observed in many laboratory anxiety models. The present study analyzed the performance of female RLA-I and RHA-I rats in a successive positive contrast situation induced during one-way avoidance learning. Three groups of RLA-I and three of RHA-I rats (1–30, 30–30 and 1–1 groups, the numbers stand for the time spent in the safe compartment during the first and second phase of training) were trained to avoid an electric foot-shock administered in a “danger” compartment, by running from this compartment to a “safe” one. Only RLA-I rats showed a significant positive contrast effect, in such a way that the reinforcement increase from the lower (1 s spent in safety) to the higher reward (30 s) led to a response enhancement, surpassing the performance of rats trained with the low (1–1 s) or the high (30–30 s) reward from the beginning of training. The results are discussed in the context of an opponent process theory based upon the interaction between the motivational strength of fear and the incentive value of relief taking place during one-way avoidance learning. [Copyright &y& Elsevier]

Abstract: The inbred RLA (Roman Low-Avoidance) and RHA (Roman High-avoidance) rat strains have been psychogenetically selected for rapid (RHA) vs. extremely poor acquisition (RLA) of two-way active avoidance. As a consequence of this selective breeding, RLA animals exhibit a higher level of emotionality that can be observed in many anxiety models. The present study was conducted in order to analyze the performance of female RLA, RHA and Wistar rats in a behavioral test of anxiety that involves the reduction of the magnitude of an expected reward: the negative contrast effect that is obtained in one-way avoidance learning by reducing the time spent in the safe compartment. To this aim, three groups of animals (30–1/RLA, 30–1/RHA and 30–1/W) were trained to avoid an electric foot-shock administered in a “danger” compartment, by running from this compartment to a “safe” compartment. We observed an impairment of the avoidance response when time spent in the safe compartment was reduced from 30 to 1 s, when 30–1/RLA and 30–1/W groups were compared with control groups that were trained with a constant safe time (1–1/RLA and 1–1/W, respectively). We also obtained significant differences between 30–1/RLA and 30–1/RHA groups in the postshift phase. These results indicate that RLA rats respond more negatively to the frustration triggered by the reduction in time spent in the safe compartment, suggesting that animal models based on negative contrast effects can be useful tools for studying the genetic basis of anxiety. [Copyright &y& Elsevier]