Effects of Degraded Optical Conditions on Behavioural Responses to Alarm Cues in a Freshwater Fish

Prey organisms often use multiple sensory cues to gain reliable information about imminent predation threat. In this study we test if a freshwater fish increases the reliance on supplementary cues when the reliability of the primary cue is reduced. Fish commonly use vision to evaluate predation threat, but may also use chemical cues from predators or injured conspecifics. Environmental changes, such as increasing turbidity or water colour, may compromise the use of vision through changes in the optical properties of water. In an experiment we tested if changes in optical conditions have any effects on how crucian carp respond to chemical predator cues. In turbidity treatments we added either clay or algae, and in a brown water colour treatment we added water with a high humic content. We found that carp reduced activity in response to predator cues, but only in the turbidity treatments (clay, algae), whereas the response in the brown water treatment was intermediate, and not significantly different from, clear and turbid water treatments. The increased reliance on chemical cues indicates that crucian carp can compensate for the reduced information content from vision in waters where optical conditions are degraded. The lower effect in brown water may be due to the reduction in light intensity, changes in the spectral composition (reduction of UV light) or to a change in chemical properties of the cue in humic waters

Early changes in Orthopteran assemblages after grassland restoration : a comparison of space-for-time substitution versus repeated-measures monitoring

Grasslands harbour significant biodiversity and their restoration is a common intervention in biodiversity conservation. However, we know very little on how grassland restoration influences arthropod groups. Here we compared orthopteran assemblages in croplands, natural grasslands and one to four-year-old grasslands restored in a large-scale restoration on former croplands in Hortobágy National Park (E-Hungary). Sampling was done by standardized sweep-netting both in a repeated measures design and space-for-time substitution (chronosequence) design. General linear models with repeated measures from five years showed that species richness, abundance and Shannon diversity of orthopterans decreased in the year following restoration but increased afterwards. By the fourth year, species richness almost doubled and abundance increased almost ten-fold in restored grasslands compared to croplands. Multivariate analyses showed that species composition in the first two years did not progress much but by the third and fourth year there was partial overlap with natural grasslands. Local restoration conditions (last crop, seed mixture) and landscape configuration (proportion of natural grasslands < 1 km away) did not influence the above patterns in either the repeated measures or the chronosequence design, whereas time since restoration affected almost all community variables. Our results suggest that generalist ubiquitous species appeared in restored grasslands first and the more sensitive species colonized the restored fields gradually in later years. The qualitative and quantitative properties of the orthopteran assemblages in restored fields did not yet reach those of natural grasslands, therefore, our study suggests that the full regeneration of the orthopteran assemblages takes more than four years

Investigation of immune and CNS-mediated effects of fingolimod in the focal delayed-type hypersensitivity multiple sclerosis model.

We examined the effect of fingolimod (0.1 and 0.3 mg/kg/day orally) on blood-brain barrier (BBB) function, demyelination and leukocyte recruitment at different stages of the focal delayed-type hypersensitivity (DTH) multiple sclerosis model in Lewis rats using immunohistochemistry and gadolinium (Gd)-enhancing magnetic resonance imaging (MRI). During DTH lesion formation, fingolimod reduced BBB breakdown (52%; p = 0.05), and lymphocyte (53%; p = 0.016) and macrophage/activated microglia (49%; p = 0.002) recruitment to the DTH lesion compared with vehicle-treated controls. Following DTH lesion establishment, fingolimod reduced the area of BBB breakdown (75%; p = 0.04), lymphocyte recruitment to the DTH lesion (41%; p = 0.01) and activated microglia outside of the lesion core (p = 0.01), but did not reduce recruitment of macrophages/activated microglia within the DTH lesion. During the chronic disease phase, when the BBB was resealed, fingolimod reduced the area of demyelination by 43% (p = 0.019) compared with vehicle-treated controls, while not affecting lymphocyte recruitment within the lesion. Fingolimod had different beneficial effects during different stages of DTH, reducing BBB breakdown and lesion development/brain tissue damage whilst reducing lymphocyte recruitment when BBB breakdown was apparent, but reducing demyelination independent of lymphocyte infiltration behind an intact BBB. These results suggest a direct CNS effect of fingolimod in this model

Investigation of immune and CNS-mediated effects of fingolimod in the focal delayed-type hypersensitivity multiple sclerosis model.

We examined the effect of fingolimod (0.1 and 0.3 mg/kg/day orally) on blood-brain barrier (BBB) function, demyelination and leukocyte recruitment at different stages of the focal delayed-type hypersensitivity (DTH) multiple sclerosis model in Lewis rats using immunohistochemistry and gadolinium (Gd)-enhancing magnetic resonance imaging (MRI). During DTH lesion formation, fingolimod reduced BBB breakdown (52%; p = 0.05), and lymphocyte (53%; p = 0.016) and macrophage/activated microglia (49%; p = 0.002) recruitment to the DTH lesion compared with vehicle-treated controls. Following DTH lesion establishment, fingolimod reduced the area of BBB breakdown (75%; p = 0.04), lymphocyte recruitment to the DTH lesion (41%; p = 0.01) and activated microglia outside of the lesion core (p = 0.01), but did not reduce recruitment of macrophages/activated microglia within the DTH lesion. During the chronic disease phase, when the BBB was resealed, fingolimod reduced the area of demyelination by 43% (p = 0.019) compared with vehicle-treated controls, while not affecting lymphocyte recruitment within the lesion. Fingolimod had different beneficial effects during different stages of DTH, reducing BBB breakdown and lesion development/brain tissue damage whilst reducing lymphocyte recruitment when BBB breakdown was apparent, but reducing demyelination independent of lymphocyte infiltration behind an intact BBB. These results suggest a direct CNS effect of fingolimod in this model

Shared-Autonomy Navigation for Mobile Robots Driven by a Door Detection Module

Shared-autonomy approaches are the most appealing for what concerns the control of assistive devices such as wheelchairs and mobile robots, designed to aid disabled and elderly people. In this paper, we propose a shared-autonomy navigation for mobile robots, that combines the user\u2019s interaction as well as the robots\u2019 perception and the environment knowledge, with the information of important landmarks, namely the doors. In order to facilitate the control of the robot, our system exploits a door detection module, aiming to detect doors and especially to identify their open/close status, making the robot pass through narrow doorways without any user\u2019s intervention. We tested the proposed system on a real mobile robot to verify the feasibility

Towards partner-aware humanoid robot control under physical interactions

The topic of physical human-robot interaction received a lot of attention from the robotics community because of many promising application domains. However, studying physical interaction between a robot and an external agent, like a human or another robot, without considering the dynamics of both the systems may lead to many short-comings in fully exploiting the interaction. In this paper, we present a coupled-dynamics formalism followed by a sound approach in exploiting helpful interaction with a humanoid robot. In particular, we propose the first attempt to define and exploit the human help for the robot to accomplish a specific task. As a result, we present a task-based partner-aware robot control techniques. The theoretical results are validated by conducting experiments with two iCub humanoid robots involved in physical interaction.Comment: Accepted to Intelligent Systems 2019 Conferenc