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Evidências sugerem que a patogênese de desordens reprodutivas, tais como a infertilidade, pode envolver perturbações no eixo hipotalâmico relacionadas ao estresse físico ou emocional. Este estudo se refere a uma revisão bibliográfica que busca reunir informações acerca do funcionamento dos hormônios reprodutivos sob condições de estresse como possível causa psicossomática da infertilidade.

Presented at the GHRSST XXIII international science team meeting, 27 June-1 July 2022, online and in-person (Barcelona). #GHRSST23 Short abstract The North Atlantic is characterised by dipole sea surface temperature (SST) differences that result from the regional segments of the global thermohaline circulation: While such Sea Surface Temperature (SST) patterns are well documented, more recently, attention has also been drawn to the urgency of detecting and predicting marine heatwaves (MHW). Like their atmospheric counterparts, MHWs have been associated with anthropogenic climate change, impacting both the marine fauna (e.g., coral bleaching, megafauna mortality, species-range shift) and flora (e.g., dieback of kelp forests, harmful algal blooms). In this study, 39 years of remotely sensed SST observations are used to identify spatio-temporal patterns of MHWs in the N. Atlantic (1982-2020 period). The 0.25˚ spatial resolution data is subject to MHW detection using the deviation from the climatological 90th percentile during at least 5 days as the criteria to measure pixel-wise anomalies. Results show that MHW events are becoming more frequent in the westernmost North Atlantic region, particularly in the Gulf Stream - this zonal pattern agrees with the typical N. Atlantic dipole SST gradient, which is shown to be increasing. Conversely, MHW intensity trends – both mean magnitude and maximum amplitude – reveal the polar amplification signal, i.e., the greatest increases are detected in the northernmost region, where the mean rate of intensity reaches up to 1ºC change, per decade.

This paper addresses the problem of time-varying bearing formation control in $d$ $(d\ge 2)$-dimensional Euclidean space by exploring Persistence of Excitation (PE) of the desired bearing reference. A general concept of Bearing Persistently Exciting (BPE) formation defined in $d$-dimensional space is here fully developed. By providing a desired formation that is BPE, distributed control laws for multi-agent systems under both single- and double-integrator dynamics are proposed using bearing measurements (along with velocity measurements when the agents are described by double-integrator dynamics), which guarantee uniform exponential stabilization of the desired formation in terms of shape and scale. A key contribution of this work is to show that the classical bearing rigidity condition on the graph topology, required for achieving the stabilization of a formation up to a scaling factor, is relaxed and extended in a natural manner by exploring PE conditions imposed either on a specific set of desired bearing vectors or on the whole desired formation. Simulation results are provided to illustrate the performance of the proposed control method., arXiv admin note: text overlap with arXiv:2009.00209

This paper considers the problem of controlling a quadrotor to go through a window and land on a planar target, the landing pad, using an Image-Based Visual Servo (IBVS) controller that relies on sensing information from two on-board cameras and an IMU. The maneuver is divided into two stages: crossing the window and landing on the pad. For the first stage, a control law is proposed that guarantees that the vehicle will not collide with the wall containing the window and will go through the window with non-zero velocity along the direction orthogonal to the window, keeping at all times a safety distance with respect to the window edges. For the landing stage, the proposed control law ensures that the vehicle achieves a smooth touchdown, keeping at all time a positive height above the plane containing the landing pad. For control purposes, the centroid vectors provided by the combination of the spherical image measurements of a collection of landmarks (corners) for both the window and the landing pad are used as position measurement. The translational optical flow relative to the wall, window edges, and landing plane is used as velocity cue. To achieve the proposed objective, no direct measurements nor explicit estimate of position or velocity are required. Simulation and experimental results are provided to illustrate the performance of the presented controller.

This is a complementary document to the paper presented in [1], to provide more detailed proofs for some results. The main paper addresses the problem of trajectory tracking control of autonomous rotorcraft in operation scenarios where only relative position measurements obtained from LiDAR sensors are possible. The proposed approach defines an alternative kinematic model, directly based on LiDAR measurements, and uses a trajectory-dependent error space to express the dynamic model of the vehicle. An LPV representation with piecewise affine dependence on the parameters is adopted to describe the error dynamics over a set of predefined operating regions, and a continuous-time $H_2$ control problem is solved using LMIs and implemented within the scope of gain-scheduling control theory., Comment: [1] B. J. Guerreiro, C. Silvestre, R. Cunha, and D. Cabecinhas, Lidar-based control of autonomous rotorcraft for the inspection of pier-like structures, IEEE Transactions in Control Systems Technology, 2017. (to appear)

Tese de mestrado, Ciências Geofísicas (Meteorologia e Oceanografia) Universidade de Lisboa, Faculdade de Ciências, 2019 Submitted by Teresa Boa (tdboa@fc.ul.pt) on 2020-01-22T14:52:14Z No. of bitstreams: 1 ulfc125670_tm_Rita_Cunha.pdf: 7046449 bytes, checksum: d8d2f41615daafc453fb7422ae0c579b (MD5) Made available in DSpace on 2020-01-22T14:52:29Z (GMT). No. of bitstreams: 1 ulfc125670_tm_Rita_Cunha.pdf: 7046449 bytes, checksum: d8d2f41615daafc453fb7422ae0c579b (MD5) Previous issue date: 2019