Mixed Analog Digital Simulation of Integrated Circuits with BRASIL

In this paper the approach of BRASIL in modelling digitalintegrated circuits is presented. BRASIL consists of a timingsimulator for digital MOS circuits coupled with an algorithmfor circuit simulation. The timing simulation is based upon afast macromodelling approach and the calculation of time-variantRC networks. The circuit simulator takes advantage of structuringthe system of nodal equations. With BRASIL a fast and accuratesimulation of digital circuits, with special regard to the analogbehaviour of highly integrated systems is possible.     

Effective single-band Hamiltonian for electron-phonon coupling in cuprate superconductors

We derive an effective single-band Hubbard type Hamiltonian for CuO₂ planes. The Hamiltonian includes both electron-electron repulsion and electron-phonon coupling to oxygen vibrational modes. We start with first-principles density functional theory parameters and then map onto a single-band model. Unlike previous mappings to a single-band Hamiltonian, ours explicitly preserves the Fermi surface shape and matrix elements of the many-band Hamiltonian. We consider both in-plane oxygen breathing modes as well as out-of-plane tilting modes. The latter modes have a quadratic electron-phonon coupling, and are also highly anharmonic in La₂CuO₄ based superconductors. The coupling to breathing modes is too small to account for highT _c, while the coupling to quadratic modes is much stronger even though they would be neglected in a standard Migdal-Eliashberg approach to superconductivity.     

Cognitive load and instructionally supported learning with provided and learner-generated visualizations

This study investigated, whether learning from science texts can be enhanced by providing learners with different forms of visualizations (pictures) in addition to text. One-hundred-two 9th and 10th graders read a computer-based text on chemical processes of washing and answered questions on cognitive load (mental effort, perceived difficulty) and comprehension (retention, transfer, drawing). Instruction varied according to a 2 × 2-factorial design with ‘learner-generated pictures’ (yes, no) and ‘provided pictures’ (yes, no) as factors. Results indicate positive main effects of provided pictures on all three comprehension measures and negative main effects on both cognitive load measures. Additional analyses revealed a mediation effect of perceived difficulty on retention and transfer, that is learning with provided pictures decreased cognitive load and enhanced comprehension. Furthermore, results show a positive main effect of learner-generated pictures on drawing and mental effort, but no mediation effect. Taken together, computer-based learning with provided pictures enhances comprehension as it seems to promote active processing while reducing extraneous cognitive processing. Learners, generating pictures, however, seem to have less cognitive resources available for essential and generative processing, resulting in reduced comprehension. These results are in line with cognitive load theory, cognitive theories of multimedia learning, and generative theories of learning.     

Electrochemical corrosion behavior of carbon-based thin films in chloride ions containing electrolytes

Commercially available carbon-based thin films consisting of single layers of amorphous diamond-like carbon or multilayers of crystalline TiAlN or CrN with diamond-like carbon top coatings were evaluated in relation to their electrochemical corrosion behavior in chloride ions containing electrolytes. The hardened working steel (an alloy of 0.9% C, 4.1% Cr, 4.9% Mo, 1.8% V, 6.4% W) was used as a substrate material.The potentiodynamic corrosion behavior of coated samples was tested in 3.5 wt.% NaCl solution and Hank's balanced body solution, HBBS (0.89 wt.% NaCl, further chlorides, sulfates, carbonates and phosphates). The multi-layers TiAlN + a-C:H:W and CrN + a-C:H:W exhibited only a minor improvement in corrosion resistance. Single layers of amorphous diamond-like carbon coating without hydrogen (a-C) spall off during the corrosion tests in chloride containing media. A minor improvement of the corrosion resistance is possible. The a-C:H and the a-C:H:Si, which contain hydrogen, showed the best corrosion resistance with a 100 times lower corrosion current density.     

Integrating a flexible anthropomorphic, robot hand into the control, system of a humanoid robot

This article presents the approaches taken to integrate a novel anthropomorphic robot hand into a humanoid robot. The requisites enabling such a robot hand to use everyday objects in an environment built for humans are presented. Starting from a design that resembles the human hand regarding size and movability of the mechatronical system, a low-level control system is shown providing reliable and stable controllers for single joint angles and torques, entire fingers and several coordinated fingers. Further on, the high-level control system connecting the low-level control system with the rest of the humanoid robot is presented. It provides grasp skills to the superior robot control system, coordinates movements of hand and arm and determines grasp patterns, depending on the object to grasp and the task to execute. Finally some preliminary results of the system, which is currently tested in simulations, will be presented.     

RTS-MAC: A Relative Time Synchronization MAC Protocol for Low Duty Cycle Body Sensor Networks

Emerging applications in the medical field require body sensor networks to communicate in real-time in a very energy-efficient way. An example is the Artificial Accommodation System??a set of two small active medical implants aiming at restoring accommodation of the human eye??in which sensor data have to be exchanged continuously between both eyes. To achieve energy efficiency, it is essential to operate the radios with a very low duty cycle. Therefore, idle listening and general protocol overhead must be reduced as much as possible. In this paper, we present a relative time synchronization medium access control protocol (RTS-MAC), which keeps relative time synchronization between two or more sensor nodes in a very energy-efficient manner: RTS-MAC makes use of the periodic broadcast of regular data messages and exploits the inter-arrival times to predict future arrivals within tight boundaries. Thereby, no overhead is generated for synchronization purposes, and still, idle listening is reduced to a minimum, which solely depends on the short-term accuracy of the underlying clock systems. We implemented the proposed protocol using off-the-shelf components and employed the internal low-accuracy oscillators of the microcontrollers as clock sources. Thereby, we achieved very low duty cycles close to an ideal minimum. Further, our results indicate that through omitting external crystals in favor of a minimally larger battery, the battery life of a sensor node can be prolonged.     

Der Verdacht der Simulation

The Suspicion of Simulation. A Psychiatric Case History between Appropriation and Disciplinary Action at the End of the 19th Century. This case history explores how the question of agency was dealt with historically in two developing, normative orders of deviant behaviour. Examining the institutional career of the supposed adulterer, marriage swindler, and craft baker, we can trace the different observation regimes and systems of knowledge acquisition in the prison and in psychiatry. In both institutions there was talk of simulated madness; the explanations, however, were different. For the prison doctors and civil servants, the baker was a criminal; his deviant behaviour was a matter of consciously planned-out deception. For the examining psychiatrist, on the other hand, he was mentally ill and could not be held responsible for his own behaviour.     

The Key Enzyme of the Sialic Acid Metabolism Is Involved in Embryoid Body Formation and Expression of Marker Genes of Germ Layer Formation

The bi-functional enzyme UDP-N-acetyl-2-epimerase/N-acetylmannosamine kinase (GNE) is the key enzyme of the sialic acid biosynthesis. Sialic acids are negatively charged nine carbon amino sugars and are found on most glycoproteins and many glycolipids in terminal positions, where they are involved in a variety of biological important molecular interactions. Inactivation of the GNE by homologous recombination results in early embryonic lethality in mice. Here, we report that GNE-deficient embryonic stem cells express less differentiation markers compared to wild-type embryonic stem cells. As a result, GNE-deficient embryonic stem cells fail to form proper embryoid bodies (EB) within the first day of culture. However, when culturing these cells in the presence of sialic acids for three days, also GNE-deficient embryonic stem cells form normal EBs. In contrast, when culturing these cells in sialic acid reduced medium, GNE-deficient embryonic stem cells proliferate faster and form larger EBs without any change in the expression of markers of the germ layers.     

Prediction of MS/MS data. 1. A focus on pharmaceuticals containing carboxylic acids

Metabolite identification is a necessary step in developing safe and effective drugs. Metabolite analysis typically involves rapid identification of the chemical composition of the metabolite by automated HPLC-MS methods, followed by the laborious process of identifying the structure of the metabolite. Since MS is typically utilized to identify the metabolite, it is logical to utilize MS/MS to structurally characterize the sample. However, interpretation of MS/MS data may not provide sufficient information, as fragmentation pathways are not well understood or predictable. Therefore, other more time-consuming methods of analysis are often undertaken. If the dissociation rules for low-energy MS/MS experiments were clearly defined for all classes of compounds, more information would be obtained from MS/MS data, and metabolite identification would proceed more rapidly. We are currently developing methods to define these fragmentation rules. By screening approximately 100 carboxylic acids at a time and applying knowledge of physical-organic chemistry, predictive rules are under development that describe how compounds dissociate under low-energy collision-induced dissociation conditions. Studies of carboxylic acid dissociation demonstrate that this approach is practical and reliable. Dissociation rules were predicted with a 90% success rate, when tested on acid-containing pharmaceuticals. This predictive power cannot be matched by any commercially available software. This study, and others like it, will be used to develop algorithms that more rapidly identify drug metabolites and degradation products, based on MS/MS data. Such algorithms will benefit drug development for all types of pharmaceuticals.