Object Reconfiguration with Dextrous Robot Agents

This paper addresses an object manipulation planning algorithm for dextrous robot systems consisting a multifingered hand and a robotic manipulator. A method has been developed for object reconfiguration design. The result is a new algorithm using artificial intelligence based on simulated annealing and A* search. The upper level of the manipulation system, the global planner generates the motion of the object. The lower level, the local planner deals with the motion of the agents relative to the object and the design of the contact forces. The local planner is based on simulated annealing, thus the the local minima can be avoided in the energy function of the motion with high probability. Application of the algorithm has been discussed for three robot arms

A multi-parametric screening platform for photosynthetic trait characterization of microalgae and cyanobacteria under inorganic carbon limitation.

Microalgae and cyanobacteria are considered as important model organisms to investigate the biology of photosynthesis; moreover, they are valuable sources of biomolecules for several biotechnological applications. Understanding the species-specific traits of photosynthetic electron transport is extremely important, because it contributes to the regulation of ATP/NADPH ratio, which has direct/indirect links to carbon fixation and other metabolic pathways and thus overall growth and biomass production. In the present work, a cuvette-based setup is developed, in which a combination of measurements of dissolved oxygen, pH, chlorophyll fluorescence and NADPH kinetics can be performed without disturbing the physiological status of the sample. The suitability of the system is demonstrated using a model cyanobacterium Synechocystis sp. PCC6803, as well as biofuel-candidate microalgae species, such as Chlorella sorokiniana, Dunaliella salina and Nannochloropsis limnetica undergoing inorganic carbon (Ci) limitation. Inorganic carbon limitation, induced by photosynthetic Ci uptake under continuous illumination, caused a decrease in the effective quantum yield of PSII (Y(II)) and loss of oxygen-evolving capacity in all species investigated here; these effects were largely recovered by the addition of NaHCO3. Detailed analysis of the dark-light and light-dark transitions of NADPH production/uptake and changes in chlorophyll fluorescence kinetics revealed species- and condition-specific responses. These responses indicate that the impact of decreased Calvin-Benson cycle activity on photosynthetic electron transport pathways involving several sections of the electron transport chain (such as electron transfer via the QA-QB-plastoquinone pool, the redox state of the plastoquinone pool) can be analyzed with high sensitivity in a comparative manner. Therefore, the integrated system presented here can be applied for screening for specific traits in several significant species at different stages of inorganic carbon limitation, a condition that strongly impacts primary productivity

How younger adults with psychosocial problems experienced person-centered health consultations

Much attention is focused on the social determinants of health. Family medicine is challenged with a growing number of vulnerable persons with psychosocial or lifestyle related problems. The objective of this work was to explore how vulnerable younger adults experience person-centered preventive health consultations with their general practitioner. The design and setting for this work were a secondary qualitative analysis of a randomized controlled trial (RCT) in Danish general practices. Younger adults (20-45) were consecutively invited to answer a screening questionnaire about psychosocial and lifestyle-related problems when visiting general practice (28 general practitioners (GPs)) for ordinary consultations. The 30% most vulnerable persons were invited to participate in a randomized controlled study. Intervention participants (n = 209) received a structured 1- hour ‘health consultation’ with their general practitioner focusing on resources and self-chosen goals and a 20-min follow-up after 3 months; control participants (n = 255) received usual care. At 1 year, 180 participants answered a follow-up postal questionnaire, of whom 135 answered the open-ended question: “Do you think the health consultation was worthwhile?”. This question was analyzed using qualitative content analysis. Six themes were prevalent: ‘Meeting the doctor in a different way’, ‘Supporting dialogue’, ‘Food for thought’, ‘Feeling better’, ‘Opportunity for change’, and the health consultations were ‘Not worthwhile’. Offering vulnerable younger adults a structured, person-centered preventive health consultation strengthened the doctor-patient relationship, allowed patients to reflect on their life situation, enhanced their perceived ability to cope with their problems and their belief in and ability to initiate wanted changes, thereby enhancing self-efficac

On relaxation processes in collisionless mergers

We analyze N-body simulations of halo mergers to investigate the mechanisms responsible for driving mixing in phase-space and the evolution to dynamical equilibrium. We focus on mixing in energy and angular momentum and show that mixing occurs in step-like fashion following pericenter passages of the halos. This makes mixing during a merger unlike other well known mixing processes such as phase mixing and chaotic mixing whose rates scale with local dynamical time. We conclude that the mixing process that drives the system to equilibrium is primarily a response to energy and angular momentum redistribution that occurs due to impulsive tidal shocking and dynamical friction rather than a result of chaotic mixing in a continuously changing potential. We also analyze the merger remnants to determine the degree of mixing at various radii by monitoring changes in radius, energy and angular momentum of particles. We confirm previous findings that show that the majority of particles retain strong memory of their original kinetic energies and angular momenta but do experience changes in their potential energies owing to the tidal shocks they experience during pericenter passages. Finally, we show that a significant fraction of mass (~ 40%) in the merger remnant lies outside its formal virial radius and that this matter is ejected roughly uniformly from all radii outside the inner regions. This highlights the fact that mass, in its standard virial definition, is not additive in mergers. We discuss the implications of these results for our understanding of relaxation in collisionless dynamical systems.Comment: Version accepted for Publication in Astrophysical Journal, March 20, 2007, v685. Minor changes, latex, 14 figure

Sex-related risk of heart failure in suspected or known coronary artery disease: adding a piece to the puzzle

This editorial refers to ‘Sex differences on new-onset heart failure in patients with known or suspected coronary artery disease’, by J. Núñez et al. pp. 1711–1719