Phase Synchronization and Polarization Ordering of Globally-Coupled Oscillators

We introduce a prototype model for globally-coupled oscillators in which each element is given an oscillation frequency and a preferential oscillation direction (polarization), both randomly distributed. We found two collective transitions: to phase synchronization and to polarization ordering. Introducing a global-phase and a polarization order parameters, we show that the transition to global-phase synchrony is found when the coupling overcomes a critical value and that polarization order enhancement can not take place before global-phase synchrony. We develop a self-consistent theory to determine both order parameters in good agreement with numerical results

Emergence of communities on a coevolutive model of wealth interchange

We present a model in which we investigate the structure and evolution of a random network that connects agents capable of exchanging wealth. Economic interactions between neighbors can occur only if the difference between their wealth is less than a threshold value that defines the width of the economic classes. If the interchange of wealth cannot be done, agents are reconnected with another randomly selected agent, allowing the network to evolve in time. On each interaction there is a probability of favoring the poorer agent, simulating the action of the government. We measure the Gini index, having real world values attached to reality. Besides the network structure showed a very close connection with the economic dynamic of the system.Comment: 5 pages, 7 figure

Deterministic polarization chaos from a laser diode

Fifty years after the invention of the laser diode and fourty years after the report of the butterfly effect - i.e. the unpredictability of deterministic chaos, it is said that a laser diode behaves like a damped nonlinear oscillator. Hence no chaos can be generated unless with additional forcing or parameter modulation. Here we report the first counter-example of a free-running laser diode generating chaos. The underlying physics is a nonlinear coupling between two elliptically polarized modes in a vertical-cavity surface-emitting laser. We identify chaos in experimental time-series and show theoretically the bifurcations leading to single- and double-scroll attractors with characteristics similar to Lorenz chaos. The reported polarization chaos resembles at first sight a noise-driven mode hopping but shows opposite statistical properties. Our findings open up new research areas that combine the high speed performances of microcavity lasers with controllable and integrated sources of optical chaos.Comment: 13 pages, 5 figure

A Robotic arm for optical and gamma radwaste inspection

We propose Radibot, a simple and cheap robotic arm for remote inspection, which interacts with the radwaste environment by means of a scintillation gamma detector and a video camera representing its light (< 1 kg) payload. It moves vertically thanks to a crane, while the other three degrees of freedom are obtained by means of revolute joints. A dedicated algorithm allows to automatically choose the best kinematics in order to reach a graphically selected position, while still allowing to fully drive the arm by means of a standard videogame joypad

Quality of life and anorectal malformations: a single-center experience

Purpose: The treatment and long term clinical outcomes of anorectal malformations (ARM) in children have always been the focus of pediatric surgeons. This study aimed at reporting our experience as far as long-term follow-up of ARM in children is concern. Methods: We enrolled patients treated between 1999 and 2019, and established selection criteria to choose appropriate subjects. A validated questionnaire was used to determine long-term quality of life outcomes. Results: Out of a total of 48 patients treated within the study period, 28 were enrolled in this study. Among the latter, more than 35% had at least one long-time complication, and more than 90% had a good lifestyle. Urinary and fecal continence was achieved in more than 95% of the patients using medical devices. Conclusion: This study aimed to bring up new concepts; taking into consideration all aspects of life in patients with ARM, from school life to sexuality, while evaluating fecal and urinary continence. This is essential for the improvement of the skills of the different specialists involved in the management of these patients, and for the implementation of strategies that can improve postoperative function. Most especially, it will also help improve communication between doctors to ensure an adequate transition of these children into adult life

Transumbilical laparoscopic treatment of Congenital Infantile Fibrosarcoma of the Ileum.

Congenital-Infantile Fibrosarcoma (CIF) is a malignant mesenchymal tumor representing 10-20% of soft-tissue tumors. Complete surgical resection is generally the treatment of choice. The most recurrent cytogenetic abnormality was identified as the traslocation t(12;15)(p13:q25), which bears the fusion of Tel gene EVT6 with TrkC gene. This study describes a case of infantile fibrosarcoma of the ileum in a female newborn examined for intestinal occlusion and its laparoscopic treatment

A Robotic arm for optical and gamma radwaste inspection

We propose Radibot, a simple and cheap robotic arm for remote inspection, which interacts with the radwaste environment by means of a scintillation gamma detector and a video camera representing its light (< 1 kg) payload. It moves vertically thanks to a crane, while the other three degrees of freedom are obtained by means of revolute joints. A dedicated algorithm allows to automatically choose the best kinematics in order to reach a graphically selected position, while still allowing to fully drive the arm by means of a standard videogame joypad