Ground verification of the feasibility of telepresent on-orbit servicing

In an ideal case telepresence achieves a state in which a human operator can no longer differentiate between an interaction with a real environment and a technical mediated one. This state is called transparent telepresence. The applicability of telepresence to on-orbit servicing (OOS), i.e., an unmanned servicing operation in space, teleoperated from ground in real time, is verified in this paper. For this purpose, a communication test environment was set up on the ground, which involved the Institute of Astronautics (LRT) ground station in Garching, Germany, and the European Space Agency (ESA) ground station in Redu, Belgium. Both were connected via the geostationary ESA data relay satellite ARTEMIS. Utilizing the data relay satellite, a teleoperation was accomplished in which the human operator as well as the (space) teleoperator was located on the ground. The feasibility of telepresent OOS was evaluated, using an OOS test bed at the Institute of Mechatronics and Robotics at the German Aerospace Center (DLR). The manipulation task was representative for OOS and supported real-time feedback from the haptic-visual workspace. The tests showed that complex manipulation tasks can be fulfilled by utilizing geostationary data relay satellites. For verifying the feasibility of telepresent OOS, different evaluation methods were used. The properties of the space link were measured and related to subjective perceptions of participants, who had to fulfill manipulation tasks. An evaluation of the transparency of the system, including the data relay satellite, was accomplished as well

Twelve-year investigation of copper soil concentrations shows that vineyards are at risk

During the period 2004–2015, the upper soil layer (0–20 cm) was sampled in eight agricultural production areas in Slovenia. Overall, 53, 249, 169, 139, and 413 samples were respectively taken from vegetable fields, arable cropland, hop fields, orchards, and vineyards. Copper was measured in the aqua-regia extracts of these samples using flame atomic absorption spectrometry. The minimum, maximum, average, and median concentrations were calculated for five land uses and for all eight production areas in Slovenia. Sample portions below and/or above the limit, warning, and critical concentrations of 60, 100, and 300 mg/kg, respectively, were calculated as well. The results were compared for different land uses and production areas and showed that the copper concentrations in the vegetable, arable crop, and hop fields and orchards did not exceed the critical concentration. In addition, the copper concentrations in the vineyards exceeded the critical concentration but the maximum copper concentration (508 mg/kg) was still lower than the concentrations reported from other vine-growing Mediterranean countries. Also, the copper concentrations in hop fields exhibited an increasing trend in the Celje (and Maribor) area(s)

SOX2 and SOX9 Expression in Developing Postnatal Opossum (Monodelphis domestica) Cortex

(1) Background: Central nervous system (CNS) development is characterized by dynamic changes in cell proliferation and differentiation. Key regulators of these transitions are the transcription factors such as SOX2 and SOX9. SOX2 is involved in the maintenance of progenitor cell state and neural stem cell multipotency, while SOX9, expressed in neurogenic niches, plays an important role in neuron/glia switch with predominant expression in astrocytes in the adult brain. (2) Methods: To validate SOX2 and SOX9 expression patterns in developing opossum (Monodelphis domestica) cortex, we used immunohistochemistry (IHC) and the isotropic fractionator method on fixed cortical tissue from comparable postnatal ages, as well as dissociated primary neuronal cultures. (3) Results: Neurons positive for both neuronal (TUJ1 or NeuN) and stem cell (SOX2) markers were identified, and their presence was confirmed with all methods and postnatal age groups (P4-6, P6-18, and P30) analyzed. SOX9 showed exclusive staining in non-neuronal cells, and it was coexpressed with SOX2. (4) Conclusions: The persistence of SOX2 expression in developing cortical neurons of M. domestica during the first postnatal month implies the functional role of SOX2 during neuronal differentiation and maturation, which was not previously reported in opossums

Influence of varied human movement control on task performance and feeling of telepresence

One of the main objectives in telerobotics is the development of a telemanipulation system that allows a high task performance to be achieved by simultaneously providing a high degree of telepresence. Specific mechatronic design guidelines and appropriate control algorithms as well as augmented visual, auditory, and haptic feedback systems are typical approaches adopted in this context. This work aims at formulating new design guidelines by incorporating human factors in the development process and analyzing the effects of varied human movement control on task performance and on the feeling of telepresence. While it is well known that humans are able to coordinate and integrate multiple degrees of freedom (DOF), the focus of this work is on how humans utilize rotational degrees of freedom provided by a human-system interface and if and how varied human movement control affects task performance and the feeling of telepresence. For this analysis, a telemanipulation experiment with varying degrees of freedom has been conducted. The results indicate that providing the full range of movement, even though this range is not necessary to accomplish a task, has a beneficial effect on the feeling of telepresence and task performance in terms of measured interaction forces. Further, increasing visual depth cues provided to the human operator also had a positive effect. © 2010 by the Massachusetts Institute of Technology