Some remarks on particle size effects on the abrasion of a range of Fe based alloys

The low-stress three body abrasion behaviour of a range of steels was investigated. The tests were carried out in a rubber wheel tester (according to ASTM G65-94, reapproved in 2000) at room temperature. The abrasive particles used were angular alumina particles of four different sizes. The results showed that, in general, the smaller particles (50 8m and 125 8m average size) caused more damage. With these particles, observations of surface morphology indicarted a more intense cutting and ploughing action, leading to more damage, whereas bigger particles i.e. larger 250 8m and 560 8m particles produced less damage, and their action involved more plastic deformation type wear. The 304 SS had a lower abrasion resistance than the 310 SS. For the austentic and ferritic steels the subsurface deformation was larger for impact with the coarser particles. Variations in substrate hardness had no effect on the abrasive behaviour observed. On the whole, the hardest steel (mild steel in martensitic condition) showed the higher extent of damage, irrespective of particle size

Learning a logistic regression with the help of unknown features at prediction stage

The use of features available at training time, but not at prediction time, as additional information for training models is known as learning using privileged information paradigm. In this paper, the handling of privileged features is addressed from the logistic regression perspective, commonly used in the clinical setting. Two new proposals, LOGIT+ and LRPROB+, learned with the influence of privileged features and preserving the interpretability of conventional logistic regression, are proposed. Experimental results on datasets report improvements of our proposals over the performance of traditional logistic regression learned without privileged information

Ratchet universality in the bidirectional escape from a symmetric potential well

The present work discusses symmetry-breaking-induced bidirectional escape from a symmetric metastable potential well by the application of zero-average periodic forces in the presence of dissipation. We characterized the interplay between heteroclinic instabilities leading to chaotic escape and breaking of a generalized parity symmetry leading to directed ratchet escape to an attractor either at infinity or at -infinity. Optimal enhancement of directed ratchet escape is found to occur when the wave form of the zero-average periodic force acting on the damped driven oscillator matches as closely as possible to a universal wave form, as predicted by the theory of ratchet universality. Specifically, the optimal approximation to the universal force triggers the almost complete destruction of the nonescaping basin for driving amplitudes which are systematically lower than those corresponding to a symmetric periodic force having the same period. We expect that this work could be potentially useful in the control of elementary dynamic processes characterized by multidirectional escape from a potential well, such as forced chaotic scattering and laser-induced dissociation of molecular systems, among others

Interaction between genes and lifestyle factors on obesity.

Obesity originates from a failure of the body-weight control systems, which may be affected by changing environmental influences. Basically, the obesity risk depends on two important mutually-interacting factors: (1) genetic variants (single-nucleotide polymorphisms, haplotypes); (2) exposure to environmental risks (diet, physical activity etc.). Common single-nucleotide polymorphisms at candidate genes for obesity may act as effect modifiers for environmental factors. More than 127 candidate genes for obesity have been reported and there is evidence to support the role of twenty-two genes in at least five different populations. Gene-environment interactions imply that the synergy between genotype and environment deviates from either the additive or multiplicative effect (the underlying model needs to be specified to appraise the nature of the interaction). Unravelling the details of these interactions is a complex task. Emphasis should be placed on the accuracy of the assessment methods for both genotype and lifestyle factors. Appropriate study design (sample size) is crucial in avoiding false positives and ensuring that studies have enough power to detect significant interactions, the ideal design being a nested case-control study within a cohort. A growing number of studies are examining the influence of gene-environmental interactions on obesity in either epidemiological observational or intervention studies. Positive evidence has been obtained for genes involved in adiposity, lipid metabolism or energy regulation such as PPARgamma2 (Pro12Ala), beta-adrenoceptor 2 (Gln27Glu) or uncoupling proteins 1, 2 and 3. Variants on other genes relating to appetite regulation such as melanocortin and leptin receptors have also been investigated. Examples of some recently-identified interactions are discussed

Nutrición en el enfermo con fibrosis quística

La fibrosis quística es una enfermedad que se asocia a una mutación de un gen localizado en el brazo largo del cromosoma 7. Esta enfermedad multisistémica afecta especialmente a los pulmones y al páncreas exocrino, lo cual supone el trastorno más influyente en la nutrición de estos pacientes. Generalmente, la suplementación con enzimas pancreáticas es necesaria como elemento terapéutico. La prevalencia de diabetes en esta enfermedad aumenta con la edad, mientras que la afectación hepática clínica es menos frecuente y otras complicaciones intestinales como el ileomeconial, el reflujo gastroesofágico o la obstrucción del intestino distal pueden condicionar también la malnutrición. La prevalencia de la desnutrición en los pacientes con fibrosis quística es elevada, aunque variable, y se asocia directamente con el estado pulmonar y la supervivencia. La terapia nutricional ha adquirido gran importancia ya que se asocia con un mejor crecimiento y mejora o estabilización de la función pulmonar, por lo que debe ser una parte integral del tratamiento de estos pacientes

V-tracer: a Vehicular Trace Generator for Future Predictive Maintenance

In this paper we present V-tracer, a vehicular trace generator aimed at generating realistic data about mobility of vehicles, as well as their daily operation and wear. The objectives of our approach are two: first, gathering real traces obtained by in-vehicle on-board units (OBUs), and second, as the first target is hard to achieve, generating synthetic data. The final goal will be getting all the information that would be very useful to infer and predict vehicle failures. The traces provided by our generator may be used to perform the predictive maintenance of vehicles in the near future

Central urocortin activation of sympathetic-regulated energy metabolism in Wistar rats

The corticotropin-releasing hormone (CRH) system, including CRH and urocortin (UCN), is implicated in the central control of appetite and energy metabolism. Urocortin, a recently isolated neuropeptide closely related to CRH is involved in the central signaling cascade that inhibits energy intake. When administered intracerebroventricularly and intra-hypothalamically, UCN potently decreases food intake. Receptors for UCN, while widely distributed, are expressed in hypothalamic nuclei. As the hypothalamus is involved in modulating autonomic outflow, UCN may also act as a catabolic neuropeptide to facilitate energy expenditure through sympathetic-regulated thermogenesis. To test the hypothesis that UCN also enhances regulatory energy expenditure via the activation of the sympathetic nervous system, we examined whole body oxygen consumption (VO2) and colonic temperature in male Wistar rats in response to central UCN administration. That is, the intracerebroventricular injection of 1.0 μg of UCN in male Wistar rats (n=10) significantly increased whole body oxygen consumption compared to PBS control. In addition, colonic temperature was significantly increased (Δ0.7±0.08 °C) in UCN- vs. PBS-administered rats, which was prevented by pretreatment with the ganglionic blocker chlorisondamine. These studies suggest that UCN acutely increased whole body oxygen consumption and body temperature via central activation of sympathetic outflow

Improving Roadside Unit deployment in vehicular networks by exploiting genetic algorithms

Vehicular networks make use of the Roadside Units (RSUs) to enhance the communication capabilities of the vehicles in order to forward control messages and/or to provide Internet access to vehicles, drivers and passengers. Unfortunately, within vehicular networks, the wireless signal propagation is mostly affected by buildings and other obstacles (e.g., urban fixtures), in particular when considering the IEEE 802.11p standard. Therefore, a crowded RSU deployment may be required to ensure vehicular communications within urban environments. Furthermore, some applications, notably those applications related to safety, require a fast and reliable warning data transmission to the emergency services and traffic authorities. However, communication is not always possible in vehicular environments due to the lack of connectivity even employing multiple hops. To overcome the signal propagation problem and delayed warning notification time issues, an effective, smart, cost-effective and all-purpose RSU deployment policy should be put into place. In this paper, we propose the genetic algorithm for roadside unit deployment (GARSUD) system, which uses a genetic algorithm that is capable of automatically providing an RSU deployment suitable for any given road map layout. Our simulation results show that GARSUD is able to reduce the warning notification time (the time required to inform emergency authorities in traffic danger situations) and to improve vehicular communication capabilities within different density scenarios and complexity layouts