Competing with stationary prediction strategies

In this paper we introduce the class of stationary prediction strategies and construct a prediction algorithm that asymptotically performs as well as the best continuous stationary strategy. We make mild compactness assumptions but no stochastic assumptions about the environment. In particular, no assumption of stationarity is made about the environment, and the stationarity of the considered strategies only means that they do not depend explicitly on time; we argue that it is natural to consider only stationary strategies even for highly non-stationary environments.Comment: 20 page

Thinking about growth : a cognitive mapping approach to understanding small business development

School of Managemen

Elevated circulating and placental SPINT2 is associated with placental dysfunction

Biomarkers for placental dysfunction are currently lacking. We recently identified SPINT1 as a novel biomarker; SPINT2 is a functionally related placental protease inhibitor. This study aimed to characterise SPINT2 expression in placental insufficiency. Circulating SPINT2 was assessed in three prospective cohorts, collected at the following: (1) term delivery (n = 227), (2) 36 weeks (n = 364), and (3) 24–34 weeks’ (n = 294) gestation. SPINT2 was also measured in the plasma and placentas of women with established placental disease at preterm (p = 0.028; median = 2233 pg/mL vs. controls, median = 1644 pg/mL), or delivered a small-for-gestational-age infant (p = 0.002; median = 2109 pg/mL vs. controls, median = 1614 pg/mL). SPINT2 was elevated in the placentas of patients who required delivery for preterm preeclampsia (p = 0.025). Though inflammatory cytokines had no effect, hypoxia increased SPINT2 in cytotrophoblast stem cells, and its expression was elevated in the placental labyrinth of growth-restricted rats. These findings suggest elevated SPINT2 is associated with placental insufficiency

Governing Boards and Profound Organizational Change in Hospitals

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69047/2/10.1177_107755878904600204.pd

Design and Development of a Soft Actuator for a Robot Inspired by the Octopus Arm

The octopus provides roboticists with a good example of a completely compliant structure that can however reach good levels of stiffness and then exert forces on its environment. With no rigid structures, the octopus can deform its body and fit small apertures, its arms can bend in all directions and they can even elongate. The peculiar muscular Structure of the octopus arm, named muscular hydrostat, acts in fact as a modifiable skeleton, providing stiffness when and where needed. A key point in imitating this muscular structure is that the muscular hydrostat creates a sort of antagonistic mechanism between different muscle fibres. As a consequence, the arm movements are given by a combination of contractions of part of the muscles and passive stretching of the other muscles. On one side, this reduces the contraction requirements for the single muscle; on the other side, the contractile structure must be compliant and passively stretchable. The contractile units proposed here are built with EAP (Electro-Active Polymer) technology, with a particular geometry that increases the contraction range and force, by using soft materials. Contraction tests on prototypes of the contracting units show a very good similarity with a theoretical model and support the starting hypothesis on the possibility of building a robotic octopus-like arm based on an artificial muscular hydrostat

Design and Development of a Soft Actuator for a Robot Inspired by the Octopus Arm

The octopus provides roboticists with a good example of a completely compliant structure that can however reach good levels of stiffness and then exert forces on its environment. With no rigid structures, the octopus can deform its body and fit small apertures, its arms can bend in all directions and they can even elongate. The peculiar muscular Structure of the octopus arm, named muscular hydrostat, acts in fact as a modifiable skeleton, providing stiffness when and where needed. A key point in imitating this muscular structure is that the muscular hydrostat creates a sort of antagonistic mechanism between different muscle fibres. As a consequence, the arm movements are given by a combination of contractions of part of the muscles and passive stretching of the other muscles. On one side, this reduces the contraction requirements for the single muscle; on the other side, the contractile structure must be compliant and passively stretchable. The contractile units proposed here are built with EAP (Electro-Active Polymer) technology, with a particular geometry that increases the contraction range and force, by using soft materials. Contraction tests on prototypes of the contracting units show a very good similarity with a theoretical model and support the starting hypothesis on the possibility of building a robotic octopus-like arm based on an artificial muscular hydrostat