The Transition to Reaching: Mapping Intention and Intrinsic Dynamics

The onset of directed reaching demarks the emergence of a qualitatively new skill. In this study we asked how intentional reaching arises from infants' ongoing, intrinsic movement dynamics, and how first reaches become successively adapted to the task. We observed 4 infants weekly in a standard reaching task and identified the week of first arm-extended reach, and the 2 weeks before and after onset. The infants first reached at ages ranging from 12 to 22 weeks, and they used different strategies to get the toy. 2 infants, whose spontaneous movements were large and vigorous, damped down their fast, forceful movements. The 2 quieter infants generated faster and more energetic movements to lift their arms. The infants modulated reaches in task-appropriate ways in the weeks following onset. Reaching emerges when infants can intentionally adjust the force and compliance of the arm, often using muscle coactivation. These results suggest that the infant central nervous system does not contain programs that detail hand trajectory, joint coordination, and muscle activation patterns. Rather, these patterns are the consequences of the natural dynamics of the system and the active exploration of the match between those dynamics and the task.     

An industrial application of symbolic model checking

Model checking techniques are recognized to provide reliable and copious results. Instead of examining a few cases only – as it is done in testing – model checking includes the whole state space in mathematical proofs of correctness. Yet, this completeness is seen as a drawback as the state explosion problem is hard to handle. In our industrial case study, we apply automated model checking techniques to an innovative elevator system, the TWIN by ThyssenKrupp. By means of abstraction and nondeterminism, we cope with runtime behaviour and achieve to efficiently prove our specification’s validity. The elevator’s safety requirements are exhaustively expressed in temporal logic along with real-world and algorithmic prerequisites, consistency properties, and fairness constraints. Beyond verifying system safety for an actual installation, our case study demonstrates the rewarding applicability of model checking at an industrial scale. CR subject classification  D.2.4; F.3.1; J.7 ; C.3     

A microfluidic platform for studying the effects of small temperature gradients in an incubator environment

Studies on the effects of variations in temperature and mild temperature gradients on cells, gels, and scaffolds are important from the viewpoint of biological function. Small differences in temperature are known to elicit significant variations in cell behavior and individual protein reactivity. For the study of thermal effects and gradients in vitro, it is important to develop microfluidic platforms which are capable of controlling temperature gradients in an environment which mimics the range of physiological conditions. In the present paper, such a microfluidic thermal gradient system (μTGS) system is proposed which can create and maintain a thermal gradient throughout a cell-seeded gel matrix using the hot and cold water supply integrated in the system in the form of a countercurrent heat exchanger. It is found that a uniform temperature gradient can be created and maintained in the device even inside a high temperature and high humidity environment of an incubator. With the help of a hot and cold circuit controlled from outside the incubator the temperature gradient can be regulated. A numerical simulation of the device demonstrates the thermal feature of the chip. Cell viability and activity under a thermal gradient are examined by placing human breast cancer cells in the device.     

Simulated tennis matchplay in a controlled environment

The aim of this study was to develop an exercise protocol to simulate tennis matchplay on a 'category 2' surface. Match analyses were used to form the basis for the design of the protocol. The protocol involved playing against a tennis ball serving machine. Part A of the protocol comprised 92 min 46 s of simulated tennis matchplay; Part B consisted of continuous hitting to the point of 'volitional fatigue' or when the required hitting frequency for two consecutive ball feeds could no longer be maintained. Ten elite tennis players (5 males, 5 females) volunteered to participate in the study, which was performed on an indoor tennis court (Matchplay?, En-Tout-Cas)?. Their age, body mass and estimated maximal oxygen uptake were as follows: males, 21.7±1.0 years, 73.6±2.6 kg and 58.0±1.7 ml?·?kg^?1?·?min^?1, respectively; females, 21.9±1.3 years, 62.3±2.0 kg and 42.2±0.7 ml?·?kg?·?min^?1, respectively (mean±). Heart rate, change in body mass and time to volitional fatigue were monitored. The heart rate responses of the participants to the simulated matchplay (range: 140-157 beats?·?min^?1, 73-81% peak heart rate) were consistent with the results of previous studies, for 'actual' matchplay. This protocol was successful in simulating similar physiological responses in Part A to 'actual' matchplay on a 'category 2' surface, in a controlled environment; it was also a sensitive evaluation tool of skilled performance in Part B. The current protocol may be used as a baseline protocol for studying the influence of, for example, training and dietary intervention on performance.     

An industrial application of symbolic model checking The TWIN elevator case study

Model checking techniques are recognized to provide reliable and copious results. Instead of examining a few cases only – as it is done in testing – model checking includes the whole state space in mathematical proofs of correctness. Yet, this completeness is seen as a drawback as the state explosion problem is hard to handle. In our industrial case study, we apply automated model checking techniques to an innovative elevator system, the TWIN by ThyssenKrupp. By means of abstraction and nondeterminism, we cope with runtime behaviour and achieve to efficiently prove our specification’s validity. The elevator’s safety requirements are exhaustively expressed in temporal logic along with real-world and algorithmic prerequisites, consistency properties, and fairness constraints. Beyond verifying system safety for an actual installation, our case study demonstrates the rewarding applicability of model checking at an industrial scale.     

Children’s Literature—The South Asian Picture

Abstract

The article examined the pattern and distribution of the secondary information, systems and services in China. The objects of the study include the governments role and relevant policies, the distribution of discipline-oriented systems, the development from printed material to machine readable to data bases and the influence of transition to a market economy on the operation of current systems. The study showed that the structure of the secondary information systems was established and the government has played a dominant role in developing and maintaining the systems. The article further discussed the challenge of a new social and economic environment to the systems and the possible expansion of new products and services.     

Microfluidic devices for studying heterotypic cell-cell interactions and tissue specimen cultures under controlled microenvironments

Microfluidic devices allow for precise control of the cellular and noncellular microenvironment at physiologically relevant length- and time-scales. These devices have been shown to mimic the complex in vivo microenvironment better than conventional in vitro assays, and allow real-time monitoring of homotypic or heterotypic cellular interactions. Microfluidic culture platforms enable new assay designs for culturing multiple different cell populations and∕or tissue specimens under controlled user-defined conditions. Applications include fundamental studies of cell population behaviors, high-throughput drug screening, and tissue engineering. In this review, we summarize recent developments in this field along with studies of heterotypic cell-cell interactions and tissue specimen culture in microfluidic devices from our own laboratory.