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1.
Esther Thelen Daniela Corbetta Kathi Kamm John P. Spencer Klaus Schneider Ronald F. Zernicke 《Child development》1993,64(4):1058-1098
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. 相似文献
2.
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 相似文献
3.
This investigation examined criticisms of the Bem Sex‐Role Inventory, a measure of gender orientation, and further examined its reliability and validity. Study 1 produced a two factor solution which was similar to other analyses. Study 2 demonstrated what adjectives best described males and females in American society. From the two studies, a revision of the Bem Sex‐Role Inventory was proposed with 10 items each measuring masculinity and femininity. 相似文献
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5.
Sarit K. Das Seok Chung Ioannis Zervantonakis Joseph Atnafu Roger D. Kamm 《Biomicrofluidics》2008,2(3)
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. 相似文献
6.
Antony Kamm 《International Information and Library Review》2013,45(2):183-196
AbstractThe 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. 相似文献
7.
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. 相似文献
8.
OBJECTIVE: To evaluate the utility of a follow-up skeletal survey in suspected child physical abuse evaluations. METHODS: In this prospective study, follow-up skeletal surveys were recommended for 74 children who, after an initial skeletal survey and evaluation by the Child Abuse Team, were suspected victims of physical abuse. The number and location of the fractures were recorded for the initial skeletal survey and for the follow-up skeletal survey in each case. RESULTS: Forty-eight of the 74 (65%) children returned for a follow-up skeletal survey. The follow-up skeletal survey yielded additional information in 22 of 48 patients (46%). In three patients (6%) the additional information changed the outcome of cases; child abuse was ruled out in one of these patients and abuse was confirmed in two cases. In three other patients, the follow-up skeletal survey refuted tentative skeletal findings, but did not change the outcome because of other physical findings. CONCLUSION: A follow-up skeletal survey identified additional fractures or clarified tentative findings in children who were suspected victims of physical child abuse. The follow-up skeletal survey should be completed on all patients who have an initial skeletal survey performed for suspected physical child abuse and for whom child abuse is still a concern. 相似文献
9.
OBJECTIVE: This study compares abnormal genital examination findings made by pediatric emergency medicine (PEM) physicians to examinations by physicians with training in child sexual abuse in the evaluation of prepubertal girls for suspected sexual abuse. METHOD: A prospective study was performed following the genital examination by a PEM physician of prepubertal girls suspected of being sexually abused. A physician with training in child sexual abuse re-examined those girls whose examinations were interpreted as abnormal by the PEM physicians. The findings and interpretations of the PEM physician were then compared to those by the physicians with training in child abuse. RESULTS: Between October 1994 and October 1998, 46 patients diagnosed by PEM physicians with nonacute genital findings indicative of sexual abuse were re-examined by a physician with training in child abuse. The follow-up examinations were done 2 days-16 weeks (mean 2.1 weeks) after the emergency department visit. The physicians with training in child abuse concluded that only eight of these children (17%) showed clear evidence of abuse. Normal findings were noted in 32 children (70%), nonspecific changes were noted in 4 children (9%), and 2 children (4%) had findings that are more commonly seen in abused children than nonabused children but are not diagnostic for abuse (concerning for abuse). CONCLUSIONS: There was poor agreement between the pediatric emergency medicine physicians and the physicians with training in child sexual abuse. This study suggests that emergency medicine physicians should consider additional training in this area. In addition, all children with abnormal ED examinations should have follow-up examinations by a child abuse trained physician. 相似文献
10.