Evolution of size-dependent flowering in Onopordum illyricum: A quantitative assessment of the role of stochastic selection pressures

We explore the evolution of delayed, size-dependent reproduction in the monocarpic perennial Onopordum illyricum, using a range of mathematical models, parameterized with long-term field data. Analysis of the long-term data indicated that mortality, flowering, and growth were age and size dependent. Using mixed models, we estimated the variance about each of these relationships and also individual-specific effects. For the held populations, recruitment was the main density-dependent process, although there were weak effects of local density on growth and mortality Using parameterized growth models, which assume plants grow along a deterministic trajectory, we predict plants should flower at sizes approximately 50% smaller than observed in the field. We then develop a simple criterion, termed the "1-yr look-ahead criterion," based on equating seed production now with that of next year, allowing for mortality and growth, to determine at what size a plant should flower. This model allows the incorporation of variance about the growth function and individual-specific effects. The model predicts flowering at sizes approximately double that observed, indicating that variance about the growth curve selects for larger sizes at flowering. The 1-yr look-ahead approach is approximate because it ignores growth opportunities more than 1 yr ahead. To assess the accuracy of this approach, we develop a more complicated dynamic state variable model. Both models give similar results indicating the utility of the 1-yr look-ahead criterion. To allow for temporal variation in the model parameters, we used an individual-based model with a generic algorithm. This gave very accurate prediction of the observed flowering strategies. Sensitivity analysis of the model suggested that temporal variation in the parameters of the growth equation made waiting to flower more risky, so selected for smaller sizes at flowering. The models clearly indicate the need to incorporate stochastic variation in life-history analyses

Experiment Definition Using the Space Laboratory, Long Duration Exposure Facility, and Space Transportation System Shuttle

Candidate experiments designed for the space shuttle transportation system and the long duration exposure facility are summarized. The data format covers: experiment title, Experimenter, technical abstract, benefits/justification, technical discussion of experiment approach and objectives, related work and experience, experiment facts space properties used, environmental constraints, shielding requirements, if any, physical description, and sketch of major elements. Information was also included on experiment hardware, research required to develop experiment, special requirements, cost estimate, safety considerations, and interactions with spacecraft and other experiments

The turbulent burning velocity of iso-octane/air mixtures

Turbulent burning velocities of iso-octane air mixtures have been measured for expanding flame kernels within a turbulent combustion bomb. High speed schlieren images were used to derive turbulent burning velocity. Turbulent velocity measurements were made at u’ = 0.5, 1.0, 2.0, 4.0, 6.0 m/s, equivalence ratios of 0.8, 1.0, 1.2, 1.4 and pressures of P = 0.1, 0.5, 1.0 MPa. The turbulent burning velocity was found to increase with time and radius from ignition, this was attributed to turbulent flame development. The turbulent burning velocity increased with increasing rms turbulent velocity, and with pressure; although differences were found in the magnitude of this increase for different turbulent velocities. Generally, raising the equivalence ratio resulted in enhanced turbulent burning velocity, excepting measurements made at the lowest turbulent velocity. The results obtained in this study have been compared with those evaluated for a number turbulent burning velocity correlations and the differences are discussed

Crystallisation in a granular material

The athermal and dissipative nature of packings of grains is still challenging our understanding of their compaction as well as their crystallisation. For instance, some beads poured in a container get jammed in random disordered con gurations, which cannot be denser than 64%, the random closed packing (RCP) limit. Remarkably it has been suggested that the RCP bound is saturated with dense patterns of beads aggregated into polytetrahedral structures. Yet when a suitable vibration is applied, a packing of beads might start to order and some regular patterns appear. We present new experiments on the crystallisation of the packing of beads. By extending tapping techniques, we have obtained packings with volume fractions φ ranging from the RCP to the crystal (φ = 0.74). Computing tomography has been used to scan the internal structure of large packings (≈200,000 beads). Voronoi and Delaunay space partitions on the grain centres were performed to characterise the structural rearrangements during the crystallisation. This allows us to describe statistical properties of the local volume uctuations and the evolution of the densest patterns of beads. In terms of statistical description, a parameter based on the volume uctuations discloses different regimes during the transition. In terms of geometry, we con rm that polytetrahedral dense clusters are ubiquitous at the RCP. We describe some intrinsic features of these clusters such as rings of tetrahedra and show how they disappear as the crystal grows. This experiment enlightens how an athermal system jammed in a complex frustrated con guration is gradually converted into a periodic crystal

Sonic Quick Response Codes (SQRC) for embedding inaudible metadata in sound files

With the advent of high definition recording and playback systems, a proportion of the ultrasonic frequency spectrum can potentially be used as a container for unperceivable data and used to trigger events or to hold metadata in the form of text, ISRC (International Standard Recording Code) or a website URL. The Sonic Quick Response Code (SQRC) algorithm is proposed as a method for embedding inaudible acoustic metadata within a 96 kHz audio file in the 30-35 kHz bandwidth range. Thus any receiver that has sufficient bandwidth and decode software installed can immediately find metadata on the audio being played. SQRC data was mixed at random periods into 96 kHz music audio files and listening subjects were asked to identify if they perceived the introduction of the high frequency content. Results show that none of the subjects in this pilot study could perceive the 30-35 kHz material. As a result, it is shown that it is possible to conduct high-resolution audio testing without significant or perceptible artifacts caused by intermodulation distortion

Clinical methods to quantify trunk mobility in an elite male surfing population

Background: Thoracic mobility in the sagittal and horizontal planes are key requirements in the sport of surfing; however to date the normal values of these movements have not yet been quantified in a surfing population. Objectives: To develop a reliable method to quantify thoracic mobility in the sagittal plane; to assess the reliability of an existing thoracic rotation method, and quantify thoracic mobility in an elite male surfing population. Design: Clinical Measurement, reliability and comparative study. Methods: A total of 30 subjects were used to determine the reliability component. 15 elite surfers were used as part of a comparative analysis with age and gender matched controls. Results: Intraclass correlation coefficient values ranged between 0.95-0.99 (95% CI; 0.89-0.99) for both thoracic methods. The elite surfing group had significantly (p ≤ 0.05) greater rotation than the comparative group (mean rotation 63.57° versus 40.80°, respectively). Conclusion: This study has illustrated reliable methods to assess the thoracic spine in the sagittal plane and thoracic rotation. It has also quantified ROM in a surfing cohort; identifying thoracic rotation as a key movement. This information may provide clinicians, coaches and athletic trainers with imperative information regarding the importance of maintaining adequate thoracic rotation. © 2015 Elsevier Ltd

The Laws of War in the Pre-Dawn Light: Institutions and Obligations in Thucydides' Peloponnesian War

This Essay in honor of Oscar Schachter criticizes both ahistorical renderings of the law of war and realist depictions of Peloponnesian War by asking whether Thucydides describes the conditions of a law of war. Examining the history in detail, Sheppard considers whether Thucydides described a sufficient institutional structure to recognize and enforce an intermunicipal law during war, as well as concepts of jus ad bellum and jus in bello. Despite the tradition of reading Thucydides as a realist, this Essay concludes that a more accurate reading would be that Thucidydes not only describes a form of a law of war but provided ample evidence of the benefits of its acceptance and the dangers of its breach