70 research outputs found
La retórica como guía para la interpretación del preludio de la Sonata No 34 en Re menor de Sylvius Leopold Weiss
Maestro (a) en MúsicaPregrad
Dietary patterns and changes in frailty status: the Rotterdam study
Purpose: To determine the associations between a priori and a posteriori derived dietary patterns and a general state of health, measured as the accumulation of deficits in a frailty index. Methods: Cross-sectional and longitudinal analysis embedded in the population-based Rotterdam Study (n = 2632) aged 45 years. Diet was assessed at baseline (year 2006) using food frequency questionnaires. Dietary patterns were defined a priori using an existing index reflecting adherence to national dietary guidelines and a posteriori using principal component analysis. A frailty index was composed of 38 health deficits and measured at baseline and follow-up (4 years later). Linear regression analyses were performed using adherence to each of the dietary patterns as exposure and the frailty index as outcome (all in Z-scores). Results: Adherence to the national dietary guidelines was associated with lower frailty at baseline (β −0.05, 95% CI −0.08, −0.02). Additionally, high adherence was associated with lower frailty scores over time (β −0.08, 95% CI −0.12, −0.04). The PCA revealed three dietary patterns that we named a “Traditional” pattern, high in legumes, eggs and savory snacks; a “Carnivore” pattern, high in meat and poultry; and a “Health Conscious” pattern, high in whole grain products, vegetables and fruit. In the cross-sectional analyses adherence to these patterns was not associated with frailty. However, adherence to the “Traditional” pattern was associated with less frailty over time (β −0.09, 95% CI −0.14, −0.05). Conclusion: No associations were found for adherence to a “healthy” pattern or “Carnivore” pattern. However, Even in a population that is relatively young and healthy, adherence to dietary guidelines or adherence to the Traditional pattern could help to prevent, delay or reverse frailty levels
Link Selection in Hybrid RF/VLC Systems under Statistical Queueing Constraints
The co-deployment of radio frequency (RF) and visible light communications (VLC) technologies has been investigated in indoor environments to enhance network performances and to address specific quality-of-service (QoS) constraints. In this paper, we explore the benefits of employing both technologies when the QoS requirements are imposed as limits on the buffer overflow and delay violation probabilities, which are important metrics in designing low latency wireless networks. Particularly, we consider a multi-mechanism scenario that utilizes RF and VLC links for data transmission in an indoor environment, and then propose a link selection process through which the transmitter sends data over the link that sustains the desired QoS guarantees the most. Considering an ON-OFF data source, we employ the maximum average data arrival rate at the transmitter buffer and the non-asymptotic bounds on data buffering delay as the main performance measures. We formulate the performance measures under the assumption that both links are subject to average and peak power constraints. Furthermore, we investigate the performance levels when either one of the two links is used for data transmission, or when both are used simultaneously. Finally, we show the impacts of different physical layer parameters on the system performance through numerical analysis
Influence of a single HELP application on hemorheology and retinal hemodynamics
The heparin-induced extracorporeal low-density lipoprotein precipitation (HELP) eliminates selectively fibrinogen, total cholesterol, low-density lipoproteins (LDL) and triglycerides and improves hemorheology. We investigated the hemodynamic changes in 10 patients without ocular diseases performing a video fluorescein angiography after a single HELP procedure measuring the arm-retina time (ART) and the arteriovenous passage time (AVP). Laboratory parameters such as fibrinogen, cholesterol, LDL, triglycerides, red cell transit time, plasma and whole-blood viscosity were determined and retinal circulation was measured immediately before and after the HELP application. All of the laboratory parameters were lowered significantly. The ART was unaffected by the HELP procedure; however, there was a significant AVP reduction from 2.41 +/- 0.49 to 1.97 +/- 0.47 (p < 0.005). These results support the hemorheological and hemodynamic efficiency of the HELP system in microcirculatory diseases
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