Performance evaluation of a second-generation elastic loop mobility system

Tests were conducted to evaluate the mobility performance of a second-generation Elastic Loop Mobility System (ELMS II). Performance on level test lanes and slopes of lunar soil simulant (LSS) and obstacle-surmounting and crevasse-crossing capabilities were investigated. In addition, internal losses and contact pressure distributions were evaluated. To evaluate the soft-soil performance, two basic soil conditions were tested: loose (LSS1) and dense (LSS5). These conditions embrace the spectrum of soil strengths tested during recent studies for NASA related to the mobility performance of the LRV. Data indicated that for the tested range of the various performance parameters, performance was independent of unit load (contact pressure) and ELMS II drum angular velocity, but was influenced by soil strength and ELMS pitch mode. Power requirements were smaller at a given system output for dense soil than for loose soil. The total system output in terms of pull developed or slope-climbing capability was larger for the ELMS II operating in restrained-pitch mode than in free-pitch mode

Performance evaluation of wheels for lunar vehicles

Performance evaluation of wheels for lunar vehicle

Vertical pairing of identical particles suspended in the plasma sheath

It is shown experimentally that vertical pairing of two identical microspheres suspended in the sheath of a radio-frequency (rf) discharge at low gas pressures (a few Pa), appears at a well defined instability threshold of the rf power. The transition is reversible, but with significant hysteresis on the second stage. A simple model, which uses measured microsphere resonance frequencies and takes into account besides Coulomb interaction between negatively charged microspheres also their interaction with positive ion wake charges, seems to explain the instability threshold quite well.Comment: 4 pages, 6 figures. to appear in Phys. Rev. Lett. 86, May 14th (2001

Attention and regional gray matter development in very preterm children at age 12 years

Objectives: This study examines the selective, sustained, and executive attention abilities of very preterm (VPT) born children in relation to concurrent structural magnetic resonance imaging (MRI) measures of regional gray matter development at age 12 years. Methods: A regional cohort of 110 VPT (≤32 weeks gestation) and 113 full term (FT) born children were assessed at corrected age 12 years on the Test of Everyday Attention-Children. They also had a structural MRI scan that was subsequently analyzed using voxel-based morphometry to quantify regional between-group differences in cerebral gray matter development, which were then related to attention measures using multivariate methods. Results: VPT children obtained similar selective (p=.85), but poorer sustained (p=.02) and executive attention (p=.01) scores than FT children. VPT children were also characterized by reduced gray matter in the bilateral parietal, temporal, prefrontal and posterior cingulate cortices, bilateral thalami, and left hippocampus; and increased gray matter in the occipital and anterior cingulate cortices (family-wise error-corrected

Low Cost Solar Array Project: Composition Measurements by Analytical Photon Catalysis

The applicability of the photon catalysis technique for effecting composition analysis of silicon samples was assessed. Third quarter activities were devoted to the study of impurities in silicon matrices. The evaporation process was shown to be congruent; thus, the spectral analysis of the vapor yields the composition of the bulk sample. Qualitative analysis of metal impurities in silicon was demonstrated e part per million level. Only one atomic spectral interference was noted; however, it is imperative to maintain a leak tight system due to chemical and spectral interferences caused by the presence of even minute amounts of oxygen in the active nitrogen afterglow

Do Actions Speak Louder than Knowledge? Action Manipulation, Parental Discourse, and Children’s Mental State Understanding in Pretense

Studies on pretense mental state understanding in young children have produced inconsistent findings. These findings could potentially emerge from the confounding influences of action manipulation or the failure to examine possible influences on individual children’s performances. To address these issues, we created a task in which 68 3- and 4-year-olds viewed two actors, side by side, on a monitor. Children were told that one actor was knowledgeable about a specific animal, whereas the other actor was not. The actors performed identical movements that were either related or unrelated to the animal they were mimicking or engaged in different behaviors contradictory to their knowledge. Saliency of action was also manipulated by presenting either dynamic images or a paused frame of the actors’ behavior (i.e., the static condition). Children performed similarly on the dynamic and static conditions. Children selected the knowledgeable actor more often in the unrelated and related trials but were not as successful at selecting the knowledgeable actor when the actor’s knowledge contradicted the actor’s behavior. Therefore, by 3 years of age, some children may understand that pretend play involves mental representations and appreciate that the mind influences a pretender’s behavior. To investigate the observed individual differences, we also examined children and parents as they engaged in reading and pretense activities prior to data collection. The frequency of parents’ cognitive mental state utterances strongly predicted performance on the mental state task. Individual differences in performance as a result of parental language and executive functioning abilities are discussed

Migrant's pursuit of happiness. The impact of adaption, social comparison and relative deprivation: Evidence from a "natural" experiment

The German reunification, which several economists have called a natural experiment, provides the unique possibility to inquire the impact of migration on subjective well-being (SWB). The main goal of the research is to assessing the impact of adaptation, social comparison and relative deprivation on the change in SWB associated with moving from Eastern to Western Germany after the German reunification in 1989. We suspect that the gains or losses in subjective well-being after migration are affected by the way migrants adapt to their new economic conditions, by with whom migrants compare themselves (that is, their reference group), their former peers in the East or their new peers in the West, and how well they integrate into the new society, that means whether they are relatively deprived with respect to earnings or not. We estimate fixed- and random-effects Generalized Least Square panel regression models. Our results indicate a positive and lasting effect of migration on SWB, although it is strongly suppressed by dissatisfaction resulting from the comparison of migrants' income with the incomes of their former peers in East Germany and the relatively higher earnings of their new peers in West Germany. Moreover, our analyses provide an explanation for the increase of SWB associated with an increase in income found in East Germany after the reunification; a deviation from the Easterlins' paradox

3D-printing based Transducer Holder for Robotic Assisted Ultrasound Guided HIFU

The InnoMotion (Synthes Inc., previously by Innomedic GmbH) is a Conformité Européene (CE) marked (in 2005) robotic system for image-guided percutaneous interventions, providing five pneumatically driven degrees of freedom (DoF) and two manually adjusted DoF. It is a fully MR and CT compatible pneumatic driven tele-manipulator for image guided insertion of cannula and probes for biopsy, drainage, drug delivery, and energetic tumor destruction. In order to achieve the robotic assisted ultrasound guided HIFU therapy, a specific holder was designed for the INNOMOTION robotic arm by using SolidWorks (Dassault Systèmes, Vélizy-Villacoublay, France). The holder provides at least seven degrees of freedom (DoF), which let the InnoMotion robotic arm hold a HIFU transducer and an ultrasound imaging probe at the same time. The HIFU transducer is mounted to the holder, while the ultrasound (US) probe could be adjusted manually to cover the expected ablation area before therapy. The main components of the holder were 3D-printed by using plastic material and were well compatible with the MR system and InnoMotion robotic arm. And the robotic assisted HIFU experiment could be performed based on this designed setup

Hereditary haemochromatosis: associations with morbidity and iron supplement use in 451,243 UK Biobank participants

This is the author accepted manuscript. The final version is available from BMJ Publishing Group via the DOI in this recordSociety for Social Medicine and Population Health and International Epidemiology Association European Congress Annual Scientific Meeting 2019, Hosted by the Society for Social Medicine & Population Health and International Epidemiology Association (IEA), School of Public Health, University College Cork, Cork, Ireland, 4–6 September 2019Medical Research Council (MRC