SECONDARY SUCCESSION OF HERBACEOUS COMMUNITIES IN JAPAN : A CASE STUDY IN SUGADAIRA, CENTRAL JAPAN

Changes of floristic composition were observed for 7 years in an experimental field of secondary succession. In the 1-year-old stand, Echinochloa crus-galli var. crus-galli was the dominant species, and Chenopodium album and Digilaria violascens were important constituent. The sequence of dominant species during the succession was Erigeron spp. (Erigeron annuus, and E. canadensis) in 2-year-old stands, and Artemisia princeps in 3-year-old stands. A. princeps maintained its dominance from 4-year-old to 7-year-old stands. Miscanthus sinensis was established in the 3-year-old stands and increased in later stages. Rumex acetosella and Oenothera parviflora were important constituent species during succession, Four stages of secondary succession were recognized in herbaceous stages by different life-forms : summer annual, biennial (winter annual), perannial herb and perennial grass. Comparing secondary succession in various sites in temoerate regions, the dominant species of each stage was similar in their life form. Raunkiaer\u27s life-form spectra change from the therophyte type in the 1-and 2-year-old stands to hemicryptophytes and chamaephytes in later stages of succession. The dominant disseminule form in the 1-year-old stand was clitochore, and anemochore increased in the later three stages. The type of life history of the dominants was the same in the same seral stage among the sites in temperate regions. Key words ; Secondary succession, Experiment, Mechanis

SARDA HITL Preliminary Human Factors Measures and Analyses

Human factors data collected during the SARDA HITL Simulation Experiment include a variety of subjective measures, including the NASA TLX, questionnaire questions regarding situational awareness, advisory usefulness, UI usability, and controller trust. Preliminary analysis of the TLX data indicate that workload may not be adversely affected by use of the advisories, additionally, the controller's subjective ratings of the advisories may suggest acceptance of the tool

Conceptualizing the adventure-sports coach

As a comparatively recent development, the adventure-sports coach struggles for a clear and distinct identity. The generic term ‘instructor’ no longer characterizes the role and function of this subgroup of outdoor professionals. Indeed, although the fields of adventure/outdoor education and leadership are comparatively well researched, the arrival of this ‘new kid on the block’ appears to challenge both the adventure-sports old guard and traditional views of sports coaching. In an attempt to offer clarity and stimulate debate, this paper attempts to conceptualize the adventure-sports coach in the context of the existing roles in the field and current motivations for activity in the outdoors. We identify issues that are specific to the adventure-sports coach while also recognizing those skills and competencies shared with other professionals, both in the adventure sports profession and traditional sports coaching fields. Based on this review, we offer a conceptual model which may be used to focus debate, stimulate research and, at a possible later stage, to underpin accreditation, training and professional development

Long-range attraction between particles in dusty plasma and partial surface tension of dusty phase boundary

Effective potential of a charged dusty particle moving in homogeneous plasma has a negative part that provides attraction between similarly charged dusty particles. A depth of this potential well is great enough to ensure both stability of crystal structure of dusty plasma and sizable value of surface tension of a boundary surface of dusty region. The latter depends on the orientation of the surface relative to the counter-ion flow, namely, it is maximal and positive for the surface normal to the flow and minimal and negative for the surface along the flow. For the most cases of dusty plasma in a gas discharge, a value of the first of them is more than sufficient to ensure stability of lenticular dusty phase void oriented across the counter-ion flow.Comment: LATEX, REVTEX4, 7 pages, 6 figure

Cost of Mating and Insemination Capacity of a Genetically Modified Mosquito Aedes aegypti OX513A Compared to Its Wild Type Counterpart

The idea of implementing genetics-based insect control strategies modelled on the traditional SIT is becoming increasingly popular. In this paper we compare a genetically modified line of Aedes aegypti carrying a tetracycline repressible, lethal positive feedback system (OX513A) with its wild type counterpart with respect to their insemination capacities and the cost of courtship and mating. Genetically modified males inseminated just over half as many females as the wild type males during their lifetime. Providing days of rest from mating had no significant effect on the total number of females inseminated by males of either line, but it did increase their longevity. Producing sperm had a low cost in terms of energy investment; the cost of transferring this sperm to a receptive female was much higher. Continued mating attempts with refractory females suggest that males could not identify refractory females before investing substantial energy in courtship. Although over a lifetime OX513A males inseminated fewer females, the number of females inseminated over the first three days, was similar between males of the two lines, suggesting that the identified cost of RIDL may have little impact on the outcome of SIT-based control programmes with frequent releases of the genetically modified males

The Moving Group Targets of the Seeds High-Contrast Imaging Survey of Exoplanets and Disks: Results and Observations from the First Three Years

We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of (is) approximately10(exp 5) at 1" and (is) approximately 10(exp 6) beyond 2" around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, beta Pictoris ((is) approximately 20 Myr), AB Doradus ((is) approximately 100 Myr), Columba ((is) approximately 30 Myr), Tucana-Horogium ((is) approximately 30 Myr), and TW Hydrae ((is) approximately 10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca ii HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, kappa And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper

The CC-NB-LRR-Type Rdg2a Resistance Gene Confers Immunity to the Seed-Borne Barley Leaf Stripe Pathogen in the Absence of Hypersensitive Cell Death

BACKGROUND: Leaf stripe disease on barley (Hordeum vulgare) is caused by the seed-transmitted hemi-biotrophic fungus Pyrenophora graminea. Race-specific resistance to leaf stripe is controlled by two known Rdg (Resistance to Drechslera graminea) genes: the H. spontaneum-derived Rdg1a and Rdg2a, identified in H. vulgare. The aim of the present work was to isolate the Rdg2a leaf stripe resistance gene, to characterize the Rdg2a locus organization and evolution and to elucidate the histological bases of Rdg2a-based leaf stripe resistance. PRINCIPLE FINDINGS: We describe here the positional cloning and functional characterization of the leaf stripe resistance gene Rdg2a. At the Rdg2a locus, three sequence-related coiled-coil, nucleotide-binding site, and leucine-rich repeat (CC-NB-LRR) encoding genes were identified. Sequence comparisons suggested that paralogs of this resistance locus evolved through recent gene duplication, and were subjected to frequent sequence exchange. Transformation of the leaf stripe susceptible cv. Golden Promise with two Rdg2a-candidates under the control of their native 5′ regulatory sequences identified a member of the CC-NB-LRR gene family that conferred resistance against the Dg2 leaf stripe isolate, against which the Rdg2a-gene is effective. Histological analysis demonstrated that Rdg2a-mediated leaf stripe resistance involves autofluorescing cells and prevents pathogen colonization in the embryos without any detectable hypersensitive cell death response, supporting a cell wall reinforcement-based resistance mechanism. CONCLUSIONS: This work reports about the cloning of a resistance gene effective against a seed borne disease. We observed that Rdg2a was subjected to diversifying selection which is consistent with a model in which the R gene co-evolves with a pathogen effector(s) gene. We propose that inducible responses giving rise to physical and chemical barriers to infection in the cell walls and intercellular spaces of the barley embryo tissues represent mechanisms by which the CC-NB-LRR-encoding Rdg2a gene mediates resistance to leaf stripe in the absence of hypersensitive cell death.Davide Bulgarelli, Chiara Biselli, Nicholas C. Collins, Gabriella Consonni, Antonio M. Stanca, Paul Schulze-Lefert and Giampiero Val