SelfVIO: Self-supervised deep monocular Visual-Inertial Odometry and depth estimation.

In the last decade, numerous supervised deep learning approaches have been proposed for visual-inertial odometry (VIO) and depth map estimation, which require large amounts of labelled data. To overcome the data limitation, self-supervised learning has emerged as a promising alternative that exploits constraints such as geometric and photometric consistency in the scene. In this study, we present a novel self-supervised deep learning-based VIO and depth map recovery approach (SelfVIO) using adversarial training and self-adaptive visual-inertial sensor fusion. SelfVIO learns the joint estimation of 6 degrees-of-freedom (6-DoF) ego-motion and a depth map of the scene from unlabelled monocular RGB image sequences and inertial measurement unit (IMU) readings. The proposed approach is able to perform VIO without requiring IMU intrinsic parameters and/or extrinsic calibration between IMU and the camera. We provide comprehensive quantitative and qualitative evaluations of the proposed framework and compare its performance with state-of-the-art VIO, VO, and visual simultaneous localization and mapping (VSLAM) approaches on the KITTI, EuRoC and Cityscapes datasets. Detailed comparisons prove that SelfVIO outperforms state-of-the-art VIO approaches in terms of pose estimation and depth recovery, making it a promising approach among existing methods in the literature.

Physiological, metabolic, and stomatal adjustments in response to salt stress in Jatropha curcas.

Salinity is a major issue affecting photosynthesis and crop production worldwide. High salinity induces both osmotic and ionic stress in plant tissues as a result of complex interactions among morphological, physiological, and biochemical processes. Salinity, in turn, can provoke inactivation of some enzymes in the Calvin-Benson cycle and therefore affect the fine adjustment of electron transport in photosystem I and carbon related reactions. Here, we used three contrasting Jatropha curcas genotypes namely CNPAE183 (considered tolerant to salinity), CNPAE218 (sensible), and JCAL171 (intermediate) to understand salinity responses. By performing a long-term (12 months) experiment in land conditions, we investigated distinct mechanisms used by J. curcas to cope with threatening salinity effects by analyzing gas exchange, mineral nutrition and metabolic responses. First, our results highlighted the plasticity of stomatal development and density in J. curcas under salt stress. It also demonstrated that the CNPAE183 presented higher salt-tolerance whereas CNPAE218 displayed a more sensitive salt-tolerance response. Our results also revealed that both tolerance and sensitivity to salinity were connected with an extensive metabolite reprogramming in the Calvin-Benson cycle and Tricarboxylic Acid cycle intermediates with significant changes in amino acids and organic acids. Collectively, these results indicate that the CNPAE183 and CNPAE218 genotypes demonstrated certain characteristics of salt-tolerant-like and salt-sensitive-like genotypes, respectively. Overall, our results highlight the significance of metabolites associated with salt responses and further provide a useful selection criterion in during screening for salt tolerance in J. curcas in breeding programmes.

The LLAMA Brazilian-Argentinian radiotelescope project: progress in Brazil and BRICS collaboration.

We present briefly the LLAMA sub-mm radiotelescope, a joint project of Argentina and Brazil, being mounted in the Andes, Argentina, at 4800 m altitude. Here we focus on the activities that are going on mostly under the responsibility of Brazil, like the high frequency receivers, parts of the back-end and electronics, the optical system of the telescope to bring the radiation to the receivers, the equipment needed for the integration and verification phase (optical telescope and holography) and the computation system.The main scientific applications that are planned are dscribed. We also report on a joint program with BRICS countries approved in 2019, which will involve the use of LLAMA for testing high-frequency receivers.

Vitrification of human embryos based on the assessment of suitable conditions for 8-cell mouse embryos.

Experiments were conducted to find a suitable cryoprotectant and suitable procedure for vitrification of 8-cell mouse embryos. The method was then applied clinically to the cryopreservation of human embryos in our assisted reproduction programme. Mouse embryos were vitrified with 30 or 40% 1,2-propanediol (PROH), dimethylsulphoxide (DMSO), ethylene glycol, glycerol, or acetamide, each diluted with a solution containing 30% Ficoll plus 0.5 M sucrose. Embryos were exposed to the solutions for 0.5 or 2 min at 20 or 25 degrees C, cooled in liquid nitrogen and warmed rapidly. Embryo survival was assessed by in-vitro development. In PROH-, DMSO- and acetamide-based solutions, higher survival rates (29-82%) were obtained with less permeating conditions, suggesting that these cryoprotectants are considerably toxic. In glycerol- and ethylene glycol-based solutions, however, higher survival rates (74 and 92% respectively) were obtained with more permeating conditions, suggesting that these cryoprotectants are less toxic. Human embryos on days 2-3 were vitrified in an ethylene glycol-based solution (EFS40). Survival, assessed by the morphology, was higher in 4-cell embryos on day 2 and 8-cell embryos on day 3 than in 2-3-cell embryos on day 2 or 2-7-cell embryos on day 3. From 18 transfers, one ended with the delivery of healthy twin babies.

Effects of hypotonic stress on the survival of mouse oocytes and embryos at various stages.

To examine the sensitivity of mammalian oocytes and embryos to osmotic swelling, which can occur during the removal of cryoprotectant from cryopreserved cells, the effect of hypotonic stress on the survival of fresh and vitrified mouse oocytes/embryos at various stages was examined. Oocytes and embryos were suspended in phosphate-buffered saline (PBS) media of various hypotonicities for 30 min at 25 degrees C. They were then returned to isotonic PBS medium, and the survival was assessed by the apparent integrity of the blastomeres and/or the developmental potential during culture. The survival of stressed embryos at one- to eight-cell stages assessed by the appearance was close to that assessed by the developmental ability, suggesting that hypotonic stress causes physical damage in the cell membrane. Fresh oocytes and embryos were almost totally unaffected by exposure to a 0.5x isotonic solution at all developmental stages examined. However, the extent of injury resulting from exposure to 0.3 to 0.2x isotonic solutions varied and depended on the developmental stage of the embryos. For example, zygotes were the least sensitive and morulae were the most sensitive to the hypotonic stresses. Except for morulae, vitrified cells were more sensitive to hypotonic stresses than were fresh ones. However, in many cases, the sensitivity was reduced or eliminated when the oocytes and embryos were cultured for a short period before exposure to the hypotonic stress. Furthermore, the survival rate of some stressed embryos which had been equilibrated in vitrification solution without cooling was higher than the survival of embryos stressed immediately following vitrification. These results show that sensitivity to osmotic swelling is variable among oocytes and embryos. The results also show that cryopreserved cells just after warming are more sensitive to osmotic swelling than are fresh ones, and even swelling corresponding to that in 0.5x solution may decrease survival in some stages.

Fracture damage of embryos and its prevention during vitrification and warming.

The frequency of fracture damage in mouse blastocysts was examined by repeated cycles of vitrification and warming. Mouse blastocysts suspended in a solution of ethylene glycol, Ficoll, and sucrose in a straw were plunged into liquid nitrogen either directly (rapidly) or after holding them in liquid nitrogen vapor for 3 min or more (moderately). Vitrified samples were warmed by plunging them into 25 degrees C water either immediately (rapidly) or after holding in air for 5-30 s (moderately). Warmed straws were recooled and rewarmed up to 9 times, to exaggerate the effect of cooling and warming. When embryos were cooled and warmed rapidly once, the incidence of the zona damage was only 1.2%, and 91% of recovered embryos reexpanded in culture. However, with repeated rapid cooling and warming, the incidence of zona damage increased, reaching 75% after 10 vitrifications; survival also dropped. When embryos were subjected to 10 cycles of moderate cooling and moderate warming with 15 or 30 s of suspension in air, 100% of the embryos had intact zonae. On the other hand, with moderate cooling followed by rapid warming or with rapid cooling followed by moderate warming, 41 and 16% of embryos had damaged zona, respectively, after 10 vitrifications. Therefore, fracture damage occurs during both cooling and warming, but it can be prevented completely by employing somewhat slower rates of cooling and warming. Furthermore, a high survival rate (88%) after 10 cycles of moderate cooling and moderate warming with 15 s of suspension in air indicates that vitrification, melting, or temperature fluctuation per se do not affect embryonic survival.