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

Impact of a child with congenital anomalies on parents (ICCAP) questionnaire; a psychometric analysis

Background: The objective of this study was to validate the Impact of a Child with Congenital Anomalies on Parents (ICCAP) questionnaire. ICCAP was newly designed to assess the impact of giving birth to a child with severe anatomical congenital anomalies (CA) on parental quality of life as a result of early stress. Methods: At 6 weeks and 6 months after birth, mothers and fathers of 100 children with severe CA were asked to complete the ICCAP questionnaire and the SF36. The ICCAP questionnaire measures six domains: contact with caregivers, social network, partner relationship, state of mind, child acceptance, and fears and anxiety. Reliability (i.e. internal consistency and test-retest) and validity were tested and the ICCAP was compared to the SF-36. Results: Confirmatory factor analysis resulted in 6 six a priori constructed subscales covering different psychological and social domains of parental quality of life as a result of early stress. Reliability estimates (congeneric approach) ranged from .49 to .92. Positive correlations with SF-36 scales ranging from .34 to .77 confirmed congruent validity. Correlations between ICCAP subscales and children's biographic characteristics, primary CA, and medical care as well as parental biographic and demographic variables ranged from -.23 to .58 and thus indicated known-group validity of the instrument. Over time both mothers an

Reproduction of natural corrosion by accelerated laboratory testing methods

Various laboratory corrosion tests have been developed to study the behavior of glass waste forms under conditions similar to those expected in an engineered repository. The data generated by laboratory experiments are useful for understanding corrosion mechanisms and for developing chemical models to predict the long-term behavior of glass. However, it is challenging to demonstrate that these test methods produce results that can be directly related to projecting the behavior of glass waste forms over time periods of thousands of years. One method to build confidence in the applicability of the test methods is to study the natural processes that have been taking place over very long periods in environments similar to those of the repository. In this paper, we discuss whether accelerated testing methods alter the fundamental mechanisms of glass corrosion by comparing the alteration patterns that occur in naturally altered glasses with those that occur in accelerated laboratory environments. This comparison is done by (1) describing the alteration of glasses reacted in nature over long periods of time and in accelerated laboratory environments and (2) establishing the reaction kinetics of naturally altered glass and laboratory reacted glass waste forms