19 research outputs found
Life history, climate and biogeography interactively affect worldwide genetic diversity of plant and animal populations.
Understanding how biological and environmental factors interactively shape the global distribution of plant and animal genetic diversity is fundamental to biodiversity conservation. Genetic diversity measured in local populations (GDP) is correspondingly assumed representative for population fitness and eco-evolutionary dynamics. For 8356 populations across the globe, we report that plants systematically display much lower GDP than animals, and that life history traits shape GDP patterns both directly (animal longevity and size), and indirectly by mediating core-periphery patterns (animal fecundity and plant dispersal). Particularly in some plant groups, peripheral populations can sustain similar GDP as core populations, emphasizing their potential conservation value. We further find surprisingly weak support for general latitudinal GDP trends. Finally, contemporary rather than past climate contributes to the spatial distribution of GDP, suggesting that contemporary environmental changes affect global patterns of GDP. Our findings generate new perspectives for the conservation of genetic resources at worldwide and taxonomic-wide scales
Lab demonstration of wavefront reconstruction for the fragmented aperture of the ELT
International audienceLab demonstration of wavefront reconstruction for the fragmented aperture of the EL
Lab demonstration of wavefront reconstruction for the fragmented aperture of the ELT
International audienceLab demonstration of wavefront reconstruction for the fragmented aperture of the EL
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Hard real-time core software of the AO RTC COSMIC platform: architecture and performance
With the upcoming giant class of telescopes, Adaptive Optics (AO) has become more essential than ever before to get access to the full potential offered by those telescopes. The complexity of such AO systems is reaching extreme heights, and disruptive developments will have to be made in order to build them. One of the critical component of a AO system is the Real Time Controller (RTC) which will have to compute the slopes and the Deformable Mirror (DM) commands at high frequency, in a range of 0.5 to several kHz. Since the complexity of the computations involved in the RTC is increasing with the size of the telescope, fulfilling RTC requirements for Extremely Large Telescope (ELT) class is a challenge. As an example, the MICADO SCAO (Single Conjugate Adaptive Optics) system requires around 1 TMAC/s for the RTC to get sufficient performance. This complexity brings the need for High Performance Computing (HPC) techniques and standards, such as the use of hardware accelerator like GPU. On top of that, building a RTC is often project-dependent as the components and the interfaces change from one instrument to an other. The COSMIC platforms aims at developing a common AO RTC platform which is meant to be powerful, modular and available to the AO community. This development is a joint effort between Observatoire de Paris and the Australian National University (ANU) in collaboration with the Subaru Telescope. We focus here on the current status of the core hard real-time component of this platform. The H-RTC pipeline is composed of Business Units (BU): each BU is an independent process in charge of one particular operation, such as Matrix Vector Multiply (MVM) or centroid computation, that can be made on CPU or on GPU. BUs read and write data on Shared Memory (SHM) handled by the CACAO framework. Synchronization between each BU can then be made either by using semaphore or by busy waiting on the GPU to ensure very low jitter. The RTC pipeline can then be controlled through a Python interface. One of the key point of this architecture is that the interfaces of a BU with the various SHM is abstracted, so adding a new BU in the collection of available ones is straight forward. This approach allows a high performance, scalable, modular and configurable RTC pipeline that could fit the needs of any AO system configuration. Performance has been measured on a MICADO SCAO scale RTC pipeline with around 25,000 slopes by 5,000 actuators on a DGX-1 system equipped with 8 Tesla V100 GPUs. The considered pipeline is composed of two BUs: the first one takes an input the raw pyramid WFS image (produced by simulator), applies on it dark and flat references, and then extract the useful pixel from the image. The second BU performs the MVM and the integration of the commands following a classical integrator command law. Synchronization between the BU is made through GPU busy waiting on the BU inputs. Performance obtained shows a mean latency up to 235 µs using 4 GPUs, with a jitter of 4.4 µs rms and a maximum jitter of 30 µs © 2020 SPIE.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Tests and characterisations of the ALPAO 64×64 deformable mirror, the MICADO-MAORY SCAO AIT facility
International audienc
Tests and characterisations of the ALPAO 64×64 deformable mirror, the MICADO-MAORY SCAO AIT facility
International audienceMICADO is the ELT near-infrared first light imager. It will provide diffraction limited images using the singleconjugate adaptive optics (SCAO) mode developed inside the MAORY AO module. Although the MICADO-MAORY SCAO mode uses during regular operations the ELT wavefront correction capabilities (M4 & M5 adaptive mirrors), the SCAO system will not be able to work with them until the final instrument commissioning. Since it is crucial to test and validate the SCAO system during various AITs phases in Europe, the need of a high order deformable mirror with comparable number of degrees of freedom is required to test both spatial and temporal behaviour of the SCAO mode. For that purpose, the SCAO AITs in Europe will use the newly developed ALPAO 64×64 actuators deformable mirror (DM). Before using this deformable mirror in the context of the SCAO mode (i.e controlled by a non-linear pyramid WFS, we built a classical Shack-Hartmann WFS to ensure a proper linear wavefront measurement in the lab and perform the DM characterisation of its 3228 actuators. We present the preliminary results of the tests performed on this DM in a classical closed loop scheme. In particular we study the spatial wavefront correction, actuators additivity and linear response, maximum amplitude range (stroke), hysteresis and temporal stability
METEORIX: a cubesat mission dedicated to the detection of meteors
International audienceHere, we present a cubesat space mission dedicated to the detection and characterization of meteors. The detection of meteors brings information on the flux of meteoroids and space debris in Earth environment and on the nature of the meteoroids that come from two reservoirs: comets and asteroids [1]. Such study brings information on the formation of the solar system. Several methods have been developed from Earth ground and airborne to detect meteors or space debris. However, the advantage of a space mission dedicated to meteors observation is to be able to probe a large volume of the Earth atmosphere and to avoid weather constraints [2]. The primary objective is to assess a robust statistics on meteoroids and space debris that enter into the Earth atmosphere. At present, their fluxes and properties are not yet determined accurately [3]. These estimates will allow to quantify the delivery of extraterrestrial material on Earth, and possible consequences on aeronomy (e.g. noctilucent clouds and atomic layer). These estimations are also crucial to estimate impact risks for artificial satellites during meteor showers. There are several secondary objectives such as to bring information on ablation, fragmentation, rotation processes by photometry variation; to determine the trajectory in connection with Earth-ground network such as FRIPON network developed in France in order to find the dynamical origin of the meteoroid; and to detect other fainter luminous atmospheric. This cubesat is a 3U developed by students from Sorbonne University and the project is presently in phase B [4]. The launch would be scheduled in four years. Support from CNES-JANUS, ESEP, and IDEX Sorbonne Universités are acknowledged.[1] Jenniskens, P., 2006, Meteor Showers and their Parent Comets. Ed. Cambridge University Press, Cambridge, U.K. [2] Bouquet A., Baratoux D., Vaubaillon J., et al. 2014, Simulation of the capabilities of an orbiter for monitoring the entry of interplanetary matter into the terrestrial atmosphere, Planetary and Space Science 103 (2014) 238-249 [3] Zolensky, M., Bland, P., Brown, P., and Halliday, I. 2006, Meteorites and the Early Solar System II, 869 [4]Meteorix, A student nanosatellite Project by UPMC - Sorbonne Universités, Phase A review, MET_MGT_HO_0068_v1r1_1109201
The cognitive, affective motivational and clinical longitudinal determinants of apathy in schizophrenia
International audienceApathy is a frequent and debilitating condition with few treatment options available in schizophrenia patients. Despite evidence of its multidimensional structure, most of past studies have explored apathy through a categorical approach. The main objective of this study was to identify the cognitive, emotional, motivational, and clinical factors at baseline that best predicted the three subtypes of apathy dimensions at follow-up. In a longitudinal study, 137 participants diagnosed with schizophrenia underwent different assessments including clinical, motivational, affective and cognitive measurements, at 1-month (referred to as baseline) and 12-month follow-ups. Data were analyzed using partial least squares variance-based structural equation modeling. Three latent variables representing the three previously described domains of apathy reaching consensus in the literature were extracted from the Lille Apathy Rating Scale. Results showed that in addition to baseline apathy, positive symptoms, anticipatory pleasure and sensibility to punishment at baseline predicted cognitive apathy at follow-up. Likewise, both baseline apathy and sensibility to punishment predicted emotional apathy at follow-up. Finally, baseline anhedonia and episodic memory were the main variables the predicted behavioral apathy at follow-up. This is the first study to show specific associations between apathy subtypes and clinical and cognitive motivational dysfunction in individual with schizophrenia, indicating possible distinct underlying mechanisms to these demotivational symptoms. Treatment for apathy should address both types of processes. Importantly, our results demonstrate the interest of multidimensional approaches in the understanding of apathy in schizophrenia
MICADO-MAORY SCAO Preliminary design, development plan & calibration strategies
International audienceMICADO is the European ELT first-light imager, working in the NIR at the telescope diffraction limit. In addition to a wide-field MCAO correction provided by MAORY, the ELT first-light adaptive optics module, MICADO will also benefit from a SCAO correction developed under MICADO's responsibility and jointly by MICADO and MAORY. In a phased approach of the AO integration at the ELT, SCAO will be the first AO mode to be tested with MICADO at the telescope and will be ultimately offered as a MAORY mode. The SCAO module is made of a pyramid wave-front sensor, a real-time computer, a dedicated calibration unit, a dichroic plate and a specific mechanical structure, all of them being associated to their corresponding electronics and (either real-time or non real-time) software. MICADO and its SCAO module have successfully passed their preliminary design review last November (2018) at ESO. In this contribution, we first present the design of the SCAO module and its different subsystems as they have been validated by the PDR board. We also present the development plan of the SCAO module, emphasizing the key milestones with their specific tests during the AIT phase. These tests comprise an on-sky experiment with the SCAO pyramid wave-front sensor and RTC prototypes, using the CANARY demonstrator at the William Herschel Telescope, as well as successive validations in lab in France, in Germany and finally in Chile. We finally make a focus on the calibrations we plan to perform until and during the operations at the telescope