Heteranthery in Clarkia: pollen performance of dimorphic anthers contradicts expectations.

Premise of the studyWild plant species that require the services of pollen-feeding insects for reliable pollination may evolve features that attract and reward their mutualistic partners. Heterantherous species have been proposed to exhibit a "division of labor" whereby "feeding anthers" (which produce pollen that may be consumed by an insect) are distinguished from "reproductive anthers" (which produce pollen more likely to contribute to reproduction). In some heterantherous species, including Clarkia unguiculata (Onagraceae), these two anther types differ with respect to stamen length, anther size, pollen production, and pollen color.MethodsThe primary goal of this study was to test one component of the "division of labor" hypothesis by comparing the performance of the pollen produced by each type of anther in C. unguiculata. To achieve this goal, under greenhouse conditions, we hand pollinated and assessed pollen performance (using epifluorescence microscopy) within ~228 flowers.Key resultsThe pollen produced by the two anther types differed significantly with respect to both stigma and style penetration. The inner series of anthers produce pollen with higher performance than the outer series of longer, dark red anthers.ConclusionsThese findings contradict previous descriptions of the genus, reporting that the inner diminutive series of anthers in Clarkia produce "abortive and nonfunctional" pollen. We outline the future research required to demonstrate the ecological function of heteranthery in this iconic wildflower group

The Ariadne's Clew Algorithm

We present a new approach to path planning, called the "Ariadne's clew algorithm". It is designed to find paths in high-dimensional continuous spaces and applies to robots with many degrees of freedom in static, as well as dynamic environments - ones where obstacles may move. The Ariadne's clew algorithm comprises two sub-algorithms, called Search and Explore, applied in an interleaved manner. Explore builds a representation of the accessible space while Search looks for the target. Both are posed as optimization problems. We describe a real implementation of the algorithm to plan paths for a six degrees of freedom arm in a dynamic environment where another six degrees of freedom arm is used as a moving obstacle. Experimental results show that a path is found in about one second without any pre-processing

The Ariadne's Clew Algorithm

We present a new approach to path planning, called the ``Ariadne's clew algorithm''. It is designed to find paths in high-dimensional continuous spaces and applies to robots with many degrees of freedom in static, as well as dynamic environments --- ones where obstacles may move. The Ariadne's clew algorithm comprises two sub-algorithms, called SEARCH and EXPLORE, applied in an interleaved manner. EXPLORE builds a representation of the accessible space while SEARCH looks for the target. Both are posed as optimization problems. We describe a real implementation of the algorithm to plan paths for a six degrees of freedom arm in a dynamic environment where another six degrees of freedom arm is used as a moving obstacle. Experimental results show that a path is found in about one second without any pre-processing

Using automatic robot programming for space telerobotics

The interpreter of a task level robot programming system called Handey is described. Handey is a system that can recognize, manipulate and assemble polyhedral parts when given only a specification of the goal. To perform an assembly, Handey makes use of a recognition module, a gross motion planner, a grasp planner, a local approach planner and is capable of planning part re-orientation. The possibility of including these modules in a telerobotics work-station is discussed

From Road to Path: The Symbolic Roles of Islam Amongst South London Gangs

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordTwo different understandings of the symbolic repertoire of Islam for young British gang members have been used in this article. Islam was used to justify participation in gang life, a function of rationalisation and protection. Islamic ideas were exploited to rationalise their criminal enterprises. The repertoire was also used to find a path out of criminality, perceived as a clear structure to finding constructive alternatives to reshape their lives. Based on 18 interviews, this paper examines these aspects of the symbolic repertoire, and shows how there is no monolithic interpretation for the role played by Islam

Endotoxemia related to cardiopulmonary bypass is associated with increased risk of infection after cardiac surgery: a prospective observational study

Abstract Introduction Previous studies have documented a high frequency of endotoxemia associated with cardiopulmonary bypass (CPB). Endotoxemia may be responsible for some of the complications associated with cardiac surgery. The purpose of the study was to examine the prevalence of endotoxemia during cardiopulmonary bypass supported aortocoronary bypass grafting surgery (ACB) using a new assay, the Endotoxin Activity Assay (EAA), and explore the association between endotoxemia and post-operative infection. Methods The study was a single center prospective observational study measuring EAA during the perioperative period for elective ACB. Blood samples were drawn at induction of anesthesia (T1), immediately prior to release of the aortic cross-clamp (T2), and on the first post-operative morning (T3). The primary outcome was the prevalence of endotoxemia. Secondary outcomes assessed included infection rates, intensive care unit (ICU) and hospital length of stay. An EAA of < 0.40 units was interpreted as "low", 0.41 to 0.59 units as "intermediate", and ≥0.60 units as "high". Results A total of 57 patients were enrolled and 54 patients were analyzable. The mean EAA at T1 was 0.38 +/- 0.14, at T2 0.39 +/- 0.18, and at T3 0.33 +/- 0.18. At T2 only 13.5% (7/52) of patients had an EAA in the high range. There was a positive correlation between EAA and duration of surgery (P = 0.02). In patients with EAA ≥0.40 at T2, 26.1% (6/23) of patients developed post-operative infections compared to 3.5% (1/29) of those that had a normal EAA (P = 0.0354). Maximum EAA over the first 24 hours was also strongly correlated with risk of post-operative infection (P = 0.0276). Conclusions High levels of endotoxin occur less frequently during ACB than previously documented. However, endotoxemia is associated with a significantly increased risk of the development of post-operative infection. Measuring endotoxin levels during ACB may provide a mechanism to identify and target a high risk patient population