Escepticismo y eticidad en la "Fenomenología del espíritu" de Hegel

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An effort to make sense of antisense transcription in bacteria

Analysis of bacterial transcriptomes have shown the existence of a genome-wide process of overlapping transcription due to the presence of antisense RNAs, as well as mRNAs that overlapped in their entire length or in some portion of the 5'- and 3'-UTR regions. The biological advantages of such overlapping transcription are unclear but may play important regulatory roles at the level of transcription, RNA stability and translation. In a recent report, the human pathogen Staphylococcus aureus is observed to generate genome-wide overlapping transcription in the same bacterial cells leading to a collection of short RNA fragments generated by the endoribonuclease III, RNase III. This processing appears most prominently in Gram-positive bacteria. The implications of both the use of pervasive overlapping transcription and the processing of these double stranded templates into short RNAs are explored and the consequences discussed

Real-time relative permeability prediction using deep learning.

A review of the existing two and three phase relative permeability correlations shows a lot of pitfalls and restrictions imposed by (a) their assumptions (b) generalization ability and (c) difficulty with updating in real time for different reservoirs systems. These increase the uncertainty in its prediction which is crucial owing to the fact that relative permeability is useful for predicting future reservoir performance, effective mobility, ultimate recovery, injectivity among others. Laboratory experiments can be time consuming, complex, expensive and done with core samples which in some circumstances may be difficult or impossible to obtain. Deep Neural Networks (DNNs) with their special capability to regularize, generalize and update easily with new data has been used to predict oil-water relative permeability. The details have been presented in this paper. In addition to common parameters influencing relative permeability, Baker and Wyllie parameter combinations were used as input to the network after comparing with other models such as Stones, Corey, Parker, Honapour using Corey and Leverett-Lewis experimental data. The DNN automatically used the best cross validation result (in a 5-fold cross validation) for its training until convergence by means of Nesterov accelerated gradient descent which also minimizes the cost function. Predictions of non-wetting and wetting phase relative permeability gave good match with field data obtained for both validation and test sets. This technique could be integrated into reservoir simulation studies, save cost, optimize the number of laboratory experiments and further demonstrates machine learning as a promising technique for real time reservoir parameters prediction

Waves in nonlinear discrete systems

Depto. de Análisis Matemático y Matemática AplicadaFac. de Ciencias MatemáticasFALSEunpu

Evolution of Surface Roughness in Grinding and its Relationship with the Dressing Parameters and the Radial Wear

Grinding is a machining process specially indicated for finishing operations in hard materials, in order to obtain low surface roughness (Ra 0.1 μm to 2μm) and tight tolerances. The cutting tool is the grinding wheel which is formed by abrasive particles attached in a bond. The wear of these abrasive particles modifies significantly the roughness obtained in the workpiece. In this work, the evolution of part roughness has been continuously monitored as the grinding process progresses and the wheel gets worn. The roughness evolution is then related to different process variables such as the dressing parameters, the grinding conditions, the grinding forces and the radial wear of the wheel

Photo-excited semiconductor superlattices as constrained excitable media: Motion of dipole domains and current self-oscillations

A model for charge transport in undoped, photo-excited semiconductor superlattices, which includes the dependence of the electron-hole recombination on the electric field and on the photo-excitation intensity through the field-dependent recombination coefficient, is proposed and analyzed. Under dc voltage bias and high photo-excitation intensities, there appear self-sustained oscillations of the current due to a repeated homogeneous nucleation of a number of charge dipole waves inside the superlattice. In contrast to the case of a constant recombination coefficient, nucleated dipole waves can split for a field-dependent recombination coefficient in two oppositely moving dipoles. The key for understanding these unusual properties is that these superlattices have a unique static electric-field domain. At the same time, their dynamical behavior is akin to the one of an extended excitable system: an appropriate finite disturbance of the unique stable fixed point may cause a large excursion in phase space before returning to the stable state and trigger pulses and wave trains. The voltage bias constraint causes new waves to be nucleated when old ones reach the contact.Comment: 19 pages, 8 figures, to appear in Phys. Rev.

Rotura no traumática de componente cerámica-cerámica en PTC: presentación de un caso y revisión de la literatura.

Las fracturas de los componentes cerámicos empleados en artroplastia total de cadera (ATC) son infrecuentes. El objetivo de nuestro trabajo es presentar un caso de rotura precoz no traumática de componente ce - rámica-cerámica en ATC y revisar la literatura en relación con esta complicación. Se trata de un paciente de 58 años diagnosticado de necrosis avascular de cabeza femoral, fue intervenido mediante ATC, implantándosele un par cerámica-cerámica. A los 4 meses de la intervención, sin antecedente traumático previo, se observó fractura de la cúpula de cerámica de la prótesis. El paciente precisó de recambio protésico, utilizándose el par cerámica-polietileno. La fractura de los componentes del par cerámica- cerámica es poco frecuente. El fallo puede ser debido a un defecto de fabricación o en la colocación del implante. Los pacientes deben ser informados sobre la posibilidad de sufrir esta complicación antes de la implantación de una PTC con par cerámica-cerámica.Fractures of ceramic components used in total hip replacement (THR) are uncommon. To report a case of early non-traumatic rupture ceramic-ceramic component in THR and review the literature regarding this complication. A 58 years diagnosed with avascular necrosis of the femoral head, was operated by THR, a ceramic-on -ceramic. At 4 months after surgery, without previous trauma, fracture was observed ceramic dome of the prosthesis. The patient required replacement, using the ceramic-on-polyethylene. The fracture of ceramic components is rare. The failure may be due to a manufacturing defect or implant placement. Patients should be informed about the possi - bility of having this complication before implantation of a THR ceramic-on-ceramic

Biovalorization of Brewery Waste by Applying Anaerobic Digestion

In the food industry, the brewing sector holds a strategic economic position: in the year 2013, the beer production of the EU-28 was equal to 383,553,000 hL. The brewing process includes chemical and biochemical reactions and solid-liquid separations, involving the generation of various residues and by-products, among which the major two fractions are brewer’s spent grain (BSG), and exhausted brewery yeast (BY). Although until today their main use has been for animal feed, in recent years, several studies have investigated the application of anaerobic digestion in order to revalue the brewery wastes. In this work, specific methane production (SMP) and first-order solubilisation (disintegration+ hydrolysis) rates (ksol) for BSG and BY were evaluated. Biomethanation tests were performed in 5-L fed-batch stirred reactors at several substrate/inoculum ratios. The obtained SMP ranged from 0.255 L CH4 g–1 COD for exhausted brewery yeast to 0.284 L CH4 g–1 COD for brewer’s spent grain. The estimated ksol values ranged from 0.224 d–1 for BSG to 0.659 d–1 for BY