Frequency response of an atomic force microscope in liquids and air: Magnetic versus acoustic excitation

We discuss the dynamics of an amplitude modulation atomic force microscope in different environments such as water and air. Experiments, analytical expressions, and numerical simulations show that the resonance curves depend on the excitation method used to drive the cantilever, either mechanical or magnetic. This dependence is magnified for small force constants and quality factors, i.e., below 1 N/m and 10, respectively. We show that the equation for the observable, the cantilever deflection, depends on the excitation method. Under mechanical excitation, the deflection involves the base and tip displacements, while in magnetic excitation, the cantilever deflection and tip displacement coincideThis work was financially supported by the European Commission (FORCETOOL) and the Ministerio de Educación y Ciencia (MAT2006-03833). We do thank stimulating discussions with J.R. Lozano, S. Patil and N.F. Martinez.Peer reviewe

Controlling Dynamic Stability and Active Compliance to Improve Quadrupedal Walking

Summary. It is widespread the idea that animal legged locomotion improves wheeled locomotion on very rough terrain. However, the use of legs as locomotion system for vehicles and robots is still far away from competing with wheels and trucks even on natural ground. Walking robots feature two main disadvantages. One is the lack of reacting capabilities from external disturbances, and the other is the very slow walking motion. Both obstacles prevent walking mechanisms from being introduced in industrial processes and from being part of service and assistance robotics. This paper is aimed at solving the two above obstacles by combining a dynamic stability margin that quantifies the impact energy that a robot can withstand, and either controlling a dynamic walk by means of active compliance, which helps the robot react to disturbances. Experiments performed on the SILO4 quadruped robot show a relevant improvement on the walking gait.This work has been partially funded by CICYT (Spain) through Grant DPI2004-05824. The first author is supported by a postdoctoral CSIC-I3P contract granted by the European Social Fund.Peer reviewe

Application of fuzzy sets in reliability calculation of the oil and gas equipment

Oil and gas equipment, and electric motors in particular, often operate in different duty cycles under changing environmental conditions. The exact effect of these factors on the equipment reliability is rather uncertain. Defining the reliability parameters as fuzzy numbers allows managing such uncertainty. The paper provides an example of fuzzy-valued reliability function estimation. Four-parameter additive Weibull distribution is considered as a reliability model with bathtubshaped failure rate function

Recommendations for reviewing a manuscript for the GMS Zeitschrift für Medizinische Ausbildung

The aim of this paper, written by the committee of educational research methodology of the “Society for Medical Education” of the German-speaking countries, will give recommendations for the review process of scientific papers in medical education. The recommendations are based on the results of a workshop in 2007 and on a survey among reviewers of the journal GMS Z Med Ausbild. It reflects on international standards and research in medical education in Germany. The paper describes reviewer’s function concerning the journal of GMS Z Med Ausbild and specifies criteria for the review process with regard to the editors and reviewers; it also gives proposals for a feedback to the author. The catalogue of criteria for the reviewers is pictured in a checklist. The present recommendations shall help to increase the quality of the review process and to improve the national and international acceptance of the journal GMS Z Med Ausbild. Additionally, transparency of the review processes will support authors to submit a scientific article of high quality

Recommendations for reviewing a manuscript for the GMS Zeitschrift für Medizinische Ausbildung

The aim of this paper, written by the committee of educational research methodology of the “Society for Medical Education” of the German-speaking countries, will give recommendations for the review process of scientific papers in medical education. The recommendations are based on the results of a workshop in 2007 and on a survey among reviewers of the journal GMS Z Med Ausbild. It reflects on international standards and research in medical education in Germany. The paper describes reviewer’s function concerning the journal of GMS Z Med Ausbild and specifies criteria for the review process with regard to the editors and reviewers; it also gives proposals for a feedback to the author. The catalogue of criteria for the reviewers is pictured in a checklist. The present recommendations shall help to increase the quality of the review process and to improve the national and international acceptance of the journal GMS Z Med Ausbild. Additionally, transparency of the review processes will support authors to submit a scientific article of high quality

Ultra-High Field MRI Post Mortem Structural Connectivity of the Human Subthalamic Nucleus, Substantia Nigra, and Globus Pallidus

Introduction: The subthalamic nucleus, substantia nigra, and globus pallidus, three nuclei of the human basal ganglia, play an important role in motor, associative, and limbic processing. The network of the basal ganglia is generally characterized by a direct, indirect, and hyperdirect pathway. This study aims to investigate the mesoscopic nature of these connections between the subthalamic nucleus, substantia nigra, and globus pallidus and their surrounding structures. Methods: A human post mortem brain specimen including the substantia nigra, subthalamic nucleus, and globus pallidus was scanned on a 7 T MRI scanner. High resolution diffusion weighted images were used to reconstruct the fibers intersecting the substantia nigra, subthalamic nucleus, and globus pallidus. The course and density of these tracks was analyzed. Results: Most of the commonly established projections of the subthalamic nucleus, substantia nigra, and globus pallidus were successfully reconstructed. However, some of the reconstructed fiber tracks such as the connections of the substantia nigra pars compacta to the other included nuclei and the connections with the anterior commissure have not been shown previously. In addition, the quantitative tractography approach showed a typical degree of connectivity previously not documented. An example is the relatively larger projections of the subthalamic nucleus to the substantia nigra pars reticulata when compared to the projections to the globus pallidus internus. Discussion: This study shows that ultra-high field post mortem tractography allows for detailed 3D reconstruction of the projections of deep brain structures in humans. Although the results should be interpreted carefully, the newly identified connections contribute to our understanding of the basal ganglia