An approach for the bimanual manipulation of a deformable linear object using a dual-arm industrial robot : cable routing use case

The automation of processes that handle deformable materials is considered to be a complicated task. Due to their properties, these materials require specialised solutions for their manipulation, using robotic systems and mostly, using specifically developed hardware which limits its use for different deformable objects. To solve this issue, this paper presents an approach for bimanually manipulating Deformable Linear Objects (DLOs) using a dual-arm industrial robot. This approach aims at providing an automatic, generic, and easily reconfigurable solution and is implemented for routing cables in a human-centric platform. The approach consists of a cyber-physical system (CPS) composed by commercial hardware: a robot equipped with two parallel grippers, and a reconfigurable Robot Operating System (ROS) software. In more details, the developed software extracts information about the process, such as the routing path, keypoints of the workstation setup and objects dimensions. Then, it uses the extracted information to generate suitable bimanual trajectories for the robot. Finally, the approach has been tested for three different routine paths.acceptedVersionPeer reviewe

Deformable objects grasping and shape detection with tactile fingers and industrial grippers

In this paper, a cyber-physical system composed by a tactile sensor, a robotic gripper and suitable ROS software nodes is proposed. The tactile sensors are shown to be compatible with three different commercial grippers, and the developed ROS nodes for the data acquisition and elaboration enable the implementation of complex tasks such as the grasping and the shape reconstruction of deformable linear objects like cables. The effectiveness of the systems is tested with cable of different diameters and with wiring harnesses composed by several cables grouped together, focusing on the reconstruction of linear and quadratic curves representing the cable shape. Experimental trials are also executed to show the possibility of exploiting the shape reconstruction provided by the proposed system to correct the gripper grasping pose

Adaptive responses to cool climate promotes persistence of a non-native lizard

Successful establishment and range expansion of non-native species often require rapid accommodation of novel environments. Here, we use common-garden experiments to demonstrate parallel adaptive evolutionary response to a cool climate in populations of wall lizards (Podarcis muralis) introduced from southern Europe into England. Low soil temperatures in the introduced range delay hatching, which generates directional selection for a shorter incubation period. Non-native lizards from two separate lineages have responded to this selection by retaining their embryos for longer before oviposition-hence reducing the time needed to complete embryogenesis in the nest-and by an increased developmental rate at low temperatures. This divergence mirrors local adaptation across latitudes and altitudes within widely distributed species and suggests that evolutionary responses to climate can be very rapid. When extrapolated to soil temperatures encountered in nests within the introduced range, embryo retention and faster developmental rate result in one to several weeks earlier emergence compared with the ancestral state. We show that this difference translates into substantial survival benefits for offspring. This should promote short- and long-term persistence of non-native populations, and ultimately enable expansion into areas that would be unattainable with incubation duration representative of the native range

Extending the motion planning framework—MoveIt with advanced manipulation functions for industrial applications

MoveIt is the primary software library for motion planning and mobile manipulation in ROS, and it incorporates the latest advances in motion planning, control and perception. However, it is still quite recent, and some important functions to build more advanced manipulation applications, required to robotize many manufacturing processes, have not been developed yet. MoveIt is an open source software, and it relies on the contributions from its community to keep improving and adding new features. Therefore, in this paper, its current state is analyzed to find out which are its main necessities and provide a solution to them. In particular, three gaps of MoveIt are addressed: the automatic tool changing at runtime, the generation of trajectories with full control over the end effector path and speed, and the generation of dual-arm trajectories using different synchronization policies. These functions have been tested with a Motoman SDA10F dual-arm robot, demonstrating their validity in different scenarios. All the developed solutions are generic and robot-agnostic, and they are openly available to be used to extend the capabilities of MoveIt.publishedVersionPeer reviewe

Alterations in deoxyribonucleic acid and proteins in cerebral tissues from fetuses subject to alcohol in utero

Critical period for intra-uterine growth retardation (IUGR), and biochemical parameters for tissue growth were studied in an animal model of Fetal Alcohol Syndrome (FAS) in rats. Our research used 40 animals, fed Lieber and DeCarli liquid diets, distributed into 4 groups: C, or control--non-alcoholic--, ad libitum; E, or alcoholic, fed ad libitum; F, or alcoholic, pair fed to E; and P, non-alcoholic, pair fed to E and F. Fetuses of group E were exposed to ethanol during the organogenic period, while those from group F exposed only during the last stage of pregnancy. Blood alcohol levels were determined both at the end of 42 days before pregnancy, and on days 3, 7, 14 and 19 of gestation. The brain content of total DNA and proteins was measured, along with the cell size of fetal tissues. Non-parametric statistics were applied, considering the litter as unit, and 5% as the significant level. Prenatal ethanol exposure was associated with a cell size, total DNA, and cerebral protein content all significantly lower (p less than or equal to 0.05) than in non-alcoholic groups. These facts strongly suggest that the critical period for growth retardation associated with FAS may be situated at the end of pregnancy, when metabolic disturbances of the brain could also arise, while major external malformations are likely to be produced during organogenesis

Darwin’s wind hypothesis: does it work for plant dispersal in fragmented habitats?

Using the wind-dispersed plant Mycelis muralis, we examined how landscape fragmentation affects variation in seed traits contributing to dispersal. Inverse terminal velocity (Vt−1) of field-collected achenes was used as a proxy for individual seed dispersal ability. We related this measure to different metrics of landscape connectivity, at two spatial scales: in a detailed analysis of eight landscapes in Spain and along a latitudinal gradient using 29 landscapes across three European regions. In the highly patchy Spanish landscapes, seed Vt−1 increased significantly with increasing connectivity. A common garden experiment suggested that differences in Vt−1 may be in part genetically based. The Vt−1 was also found to increase with landscape occupancy, a coarser measure of connectivity, on a much broader (European) scale. Finally, Vt−1 was found to increase along a south–north latitudinal gradient. Our results for M. muralis are consistent with ‘Darwin’s wind dispersal hypothesis’ that high cost of dispersal may select for lower dispersal ability in fragmented landscapes, as well as with the ‘leading edge hypothesis’ that most recently colonized populations harbour more dispersive phenotypes.

Southern African Large Telescope Spectroscopy of BL Lacs for the CTA project

In the last two decades, very-high-energy gamma-ray astronomy has reached maturity: over 200 sources have been detected, both Galactic and extragalactic, by ground-based experiments. At present, Active Galactic Nuclei (AGN) make up about 40% of the more than 200 sources detected at very high energies with ground-based telescopes, the majority of which are blazars, i.e. their jets are closely aligned with the line of sight to Earth and three quarters of which are classified as high-frequency peaked BL Lac objects. One challenge to studies of the cosmological evolution of BL Lacs is the difficulty of obtaining redshifts from their nearly featureless, continuum-dominated spectra. It is expected that a significant fraction of the AGN to be detected with the future Cherenkov Telescope Array (CTA) observatory will have no spectroscopic redshifts, compromising the reliability of BL Lac population studies, particularly of their cosmic evolution. We started an effort in 2019 to measure the redshifts of a large fraction of the AGN that are likely to be detected with CTA, using the Southern African Large Telescope (SALT). In this contribution, we present two results from an on-going SALT program focused on the determination of BL Lac object redshifts that will be relevant for the CTA observatory

Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy

Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme

Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA