Instituto Politécnico Nacional

About: Instituto Politécnico Nacional is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Population & Context (language use). The organization has 43351 authors who have published 63315 publications receiving 938532 citations. The organization is also known as: Instituto Politécnico Nacional & Instituto Politecnico Nacional.

Ustekinumab for the Treatment of Refractory Crohn's Disease: The Spanish Experience in a Large Multicentre Open-label Cohort.

Abstract: Background Ustekinumab is a fully human monoclonal antibody against IL-12/23. Ustekinumab induced clinical response and maintained higher rate of response than placebo in patients with Crohn's disease (CD). This study aims to assess the effectiveness and safety of ustekinumab in refractory patients with CD in real-life practice. Methods Consecutive patients with CD who were treated with subcutaneous ustekinumab between March 2010 and December 2014 were retrospectively included in a multicenter open-label study. Clinical response was defined by Harvey-Bradshaw index score and assessed after the loading doses, 6, 12 months, and last follow-up. Results One hundred sixteen patients were included, with a median follow-up of 10 months (interquartile range: 5-21). Clinical response after loading ustekinumab was achieved in 97/116 (84%) patients. The clinical benefit at 6, 12 months, and at the end of the follow-up was 76%, 64%, and 58%, respectively. Dose escalation was effective in 8 of 11 (73%) patients. Perianal disease also improved in 11 of 18 (61%) patients with active perianal fistulae. The initial response to ustekinumab and previous use of more than 2 immunosuppressant drugs were associated with a clinical response to ustekinumab maintenance therapy. In contrast, previous bowel resection predicted a long-term failure with ustekinumab. Adverse events were reported in 11 (9.5%) patients, but none required ustekinumab withdrawal. Conclusions Subcutaneous ustekinumab is effective and safe in a high proportion of patients with CD that were resistant to conventional immunosuppressant and antitumor necrosis factor drugs.

Analysis and design of the google congestion control for web real-time communication (WebRTC)

Abstract: Video conferencing applications require low latency and high bandwidth. Standard TCP is not suitable for video conferencing since its reliability and in order delivery mechanisms induce large latency. Recently the idea of using the delay gradient to infer congestion is appearing again and is gaining momentum. In this paper we present an algorithm that is based on estimating through a Kalman filter the end-to-end one way delay variation which is experienced by packets traveling from a sender to a destination. This estimate is compared to an adaptive threshold to dynamically throttle the sending rate. The control algorithm has been implemented over the RTP/RTCP protocol and is currently used in Google Hangouts and in the Chrome WebRTC stack. Experiments have been carried out to evaluate the algorithm performance in the case of variable link capacity, presence of heterogeneous or homogeneous concurrent traffic, and backward path traffic.

Linear active disturbance rejection control of underactuated systems: the case of the Furuta pendulum

Abstract: An Active Disturbance Rejection Control (ADRC) scheme is proposed for a trajectory tracking problem defined on a nonfeedback linearizable Furuta Pendulum example. A desired rest to rest angular position reference trajectory is to be tracked by the horizontal arm while the unactuated vertical pendulum arm stays around its unstable vertical position without falling down during the entire maneuver and long after it concludes. A linear observer-based linear controller of the ADRC type is designed on the basis of the flat tangent linearization of the system around an arbitrary equilibrium. The advantageous combination of flatness and the ADRC method makes it possible to on-line estimate and cancels the undesirable effects of the higher order nonlinearities disregarded by the linearization. These effects are triggered by fast horizontal arm tracking maneuvers driving the pendulum substantially away from the initial equilibrium point. Convincing experimental results, including a comparative test with a sliding mode controller, are presented.

The spin Hall effect in a quantum gas

Abstract: Electronic properties such as current flow are generally independent of the electron's spin angular momentum, an internal degree of freedom possessed by quantum particles. The spin Hall effect, first proposed 40 years ago, is an unusual class of phenomena in which flowing particles experience orthogonally directed, spin-dependent forces--analogous to the conventional Lorentz force that gives the Hall effect, but opposite in sign for two spin states. Spin Hall effects have been observed for electrons flowing in spin-orbit-coupled materials such as GaAs and InGaAs (refs 2, 3) and for laser light traversing dielectric junctions. Here we observe the spin Hall effect in a quantum-degenerate Bose gas, and use the resulting spin-dependent Lorentz forces to realize a cold-atom spin transistor. By engineering a spatially inhomogeneous spin-orbit coupling field for our quantum gas, we explicitly introduce and measure the requisite spin-dependent Lorentz forces, finding them to be in excellent agreement with our calculations. This 'atomtronic' transistor behaves as a type of velocity-insensitive adiabatic spin selector, with potential application in devices such as magnetic or inertial sensors. In addition, such techniques for creating and measuring the spin Hall effect are clear prerequisites for engineering topological insulators and detecting their associated quantized spin Hall effects in quantum gases. As implemented, our system realizes a laser-actuated analogue to the archetypal semiconductor spintronic device, the Datta-Das spin transistor.