Enhanced optical frequency comb generation by pulsed gain-switching of optically injected semiconductor lasers.

We report on the experimental generation of broad and flat optical frequency combs (OFC) in a 1550 nm laser diode using gain switching with pulsed electrical excitation together with optical injection. The combination of both techniques allows the generation of high-quality OFCs at a repetition frequency of 500 MHz, showing a low-noise optical spectrum with unprecedent features in terms of width (108 tones within 10 dB) and flatness (56 tones within 3 dB) in comparison with those previously reported for this modulation frequency. The influence of the injection conditions on the OFC quality is studied. Using these two techniques, it has been possible to reduce the separation between tones, generating high spectral performance OFCs with a repetition rateof 100 MHz.

Optoelectronic reservoir computing: tackling noise-induced performance degradation.

We present improved strategies to perform photonic information processing using an optoelectronic oscillator with delayed feedback. In particular, we study, via numerical simulations and experiments, the influence of a finite signal-to-noise ratio on the computing performance. We illustrate that the performance degradation induced by noise can be compensated for via multi-level pre-processing masks.

[How to prepare a poster presentation]. / Cómo preparar un póster para un congreso.

Scientific and educational poster presentations in national and international meetings are one of the most effective means of scientific communication. Poster presentations are of particular importance in a mainly visual speciality like radiology, and also play a significant role in continuing medical education in our specialty. However, poster should be no more than an intermediate step on the way to publish our work in a scientific journal. The publication rates of posters prented in courses and conferences is very low in our country. Therefore, we must continue to progress in training in scientific publication, with efforts such as this supplement. This article review how to create an effective poster presentation.

Photonic information processing beyond Turing: an optoelectronic implementation of reservoir computing.

Many information processing challenges are difficult to solve with traditional Turing or von Neumann approaches. Implementing unconventional computational methods is therefore essential and optics provides promising opportunities. Here we experimentally demonstrate optical information processing using a nonlinear optoelectronic oscillator subject to delayed feedback. We implement a neuro-inspired concept, called Reservoir Computing, proven to possess universal computational capabilities. We particularly exploit the transient response of a complex dynamical system to an input data stream. We employ spoken digit recognition and time series prediction tasks as benchmarks, achieving competitive processing figures of merit.

Current status of young urologists and residents' activity and academic training in Spain. National survey results. / Estado actual de la actividad y formación académica de residentes y urólogos jóvenes en España. Resultados de una encuesta nacional.

OBJECTIVE: To study the current status of the activity and academic training of residents and young urologists in Spain. MATERIAL AND METHODS: From the working group of residents and young urologists of the Spanish Association of Urology (AEU), an anonymous survey of 32 questions was designed. Its aim was to evaluate the academic activity of residents, defined by: number of communications to congresses, publications in national and international journals, clinical rotations within Spain and abroad, master's degree, Doctorate (PhD), applications to the European Board of Urology exam and language competences. The survey was sent via email and disseminated through social networks. RESULTS: Ninety-one respondents were obtained; 66% affirmed not having publications in scientific journals, 67% did not perform rotations abroad. Only 21% claimed to have taken the EBU exam. Only 2% of the respondents had completed a Fellowship. Although most of them (82%) had not done so, they would be interested. However, 67% of respondents believed that the relevance of academic/research activity is from high to very high. CONCLUSIONS: Our results indicate that academic activity, scientific production and publication of articles of the residents and young urologists in Spain is low. Moreover, participation in the EBU exam, the completion of a master's degree, PhD, rotations and fellowship is low. In contrast, the assessment of scientific activity is considered to be very relevant.

Medical-surgical activity and the current state of training of urology residents in Spain: Results of a national survey. / Actividad médico-quirúrgica y estado actual de la formación de los residentes de urología en España: Resultados de una encuesta nacional.

OBJECTIVES: To determine the actual state of medical-surgical activity and training for urology residents in Spain. MATERIAL AND METHOD: We designed 2 anonymous surveys, which were uploaded with the Google Docs© tool so that the respondents could answer the surveys online. The online collection period was September 2015 to January 2016. The collected data were processing using the statistical programme IBM SPSS for Windows, Version 21.0 and the programme R version 3.2.3. RESULTS: The total number of responders was 163. In reference to the number of physically present on-call residents, the majority conducted between 4 and 6 shifts a month. Eighty-four of those surveyed indicated that they were in the operating room less than 20hours a week, and 43 of these even less than 10hours. Thirty percent of those surveyed had not performed any transurethral resection. The majority had performed at least one prostatic adenomectomy, but had not performed any major oncologic procedure, either laparoscopically or openly. In the questions concerning training and training courses, we found that most of the residents trained in laparoscopy at the hospital or at home. The overall satisfaction for the residence was assessed at 2.6. Based on this score, the overall satisfaction could be considered moderate. CONCLUSIONS: Efforts should be directed towards standardising the acquisition of surgical and nonsurgical skills, ensuring access to training courses, establishing a minimum of required operations per year and achieving an objective assessment of the specialty.

Approach to predictability via anticipated synchronization.

Predictability of chaotic systems is limited, in addition to the precision of the knowledge of the initial conditions, by the error of the models used to extract the nonlinear dynamics from the time series. In this paper, we analyze the predictions obtained from the anticipated synchronization scheme using a chain of slave neural network approximate replicas of the master system. We compare the maximum prediction horizons obtained with those attainable using standard prediction techniques.

A Unified Framework for Reservoir Computing and Extreme Learning Machines based on a Single Time-delayed Neuron.

In this paper we present a unified framework for extreme learning machines and reservoir computing (echo state networks), which can be physically implemented using a single nonlinear neuron subject to delayed feedback. The reservoir is built within the delay-line, employing a number of "virtual" neurons. These virtual neurons receive random projections from the input layer containing the information to be processed. One key advantage of this approach is that it can be implemented efficiently in hardware. We show that the reservoir computing implementation, in this case optoelectronic, is also capable to realize extreme learning machines, demonstrating the unified framework for both schemes in software as well as in hardware.

Stability of a diode laser with phase-conjugate feedback.

An exact analysis is presented of the steady-state stability of a semiconductor laser subjected to feedback from a phase-conjugate mirror. Reduced stability occurs at low feedback whenever the effective external delay time is an integer multiple of the relaxation oscillation period. The role of a finite response time of the mirror is to enhance drastically the steady-state stability.