Non-random dispersal in the butterfly Maniola jurtina: implications for metapopulation models

The dispersal patterns of animals are important in metapopulation ecology because they affect the dynamics and survival of populations. Theoretical models assume random dispersal but little is known in practice about the dispersal behaviour of individual animals or the strategy by which dispersers locate distant habitat patches. In the present study, we released individual meadow brown butterflies (Maniola jurtina) in a non-habitat and investigated their ability to return to a suitable habitat. The results provided three reasons for supposing that meadow brown butterflies do not seek habitat by means of random flight. First, when released within the range of their normal dispersal distances, the butterflies orientated towards suitable habitat at a higher rate than expected at random. Second, when released at larger distances from their habitat, they used a non-random, systematic, search strategy in which they flew in loops around the release point and returned periodically to it. Third, butterflies returned to a familiar habitat patch rather than a non-familiar one when given a choice. If dispersers actively orientate towards or search systematically for distant habitat, this may be problematic for existing metapopulation models, including models of the evolution of dispersal rates in metapopulations

Pulled apart, pushed together: diversity and unity within the Congress of South African Trade Unions

This is a study of horizontal and vertical solidarity within a national labour movement, based on a nationwide survey of members of affiliated unions of the Congress of South African Trade Unions. On the one hand, the survey reveals relatively high levels of vertical and horizontal solidarity, despite the persistence of some cleavages on gender and racial lines. On the other hand, the maintenance and deepening of existing horizontal and vertical linkages in a rapidly changing socio-economic context, represents one of many challenges facing organized labour in an industrializing economy. COSATU’s strength is contingent not only on an effective organizational capacity, and a supportive network linking key actors and interest groupings, but also on the ability to meet the concerns of existing constituencies and those assigned to highly marginalized categories of labour

A High-resolution Scintillating Fiber Tracker With Silicon Photomultiplier Array Readout

We present prototype modules for a tracking detector consisting of multiple layers of 0.25 mm diameter scintillating fibers that are read out by linear arrays of silicon photomultipliers. The module production process is described and measurements of the key properties for both the fibers and the readout devices are shown. Five modules have been subjected to a 12 GeV/c proton/pion testbeam at CERN. A spatial resolution of 0.05 mm and light yields exceeding 20 detected photons per minimum ionizing particle have been achieved, at a tracking efficiency of more than 98.5%. Possible techniques for further improvement of the spatial resolution are discussed.Comment: 31 pages, 27 figures, pre-print version of an article published in Nuclear Instruments and Methods in Physics Research Section A, Vol. 62

Phenotypic and functional characterization of adult brain neuropoiesis

The modern concept of neurogenesis in the adult brain is predicated on the premise that multipotent glial cells give rise to new neurons throughout life. Although extensive evidence exists indicating that this is the case, the transition from glial to neuronal phenotype remains poorly understood. A unique monolayer cell-culture system was developed to induce, expose, and recapitulate the entire developmental series of events of subventricular zone (SVZ) neurogenesis. We show here, using immunophentoypic, ultrastructural, electrophysiological, and time-lapse analyses, that SVZ-derived glial fibrillary acidic protein(low)/A2B5(+)/nestin(+) candidate founder cells undergo metamorphosis to eventually generate large numbers of fully differentiated interneuron phenotypes. A model of postnatal neurogenesis is considered in light of known embryonic events and reveals a limited developmental potential of SVZ stem/progenitor cells, whereby ancestral cells in both embryonic and postnatal/adult settings give rise to glia and GABAergic interneurons

Differential effects of Epigallocatechin-3-gallate containing supplements on correcting skeletal defects in a Down syndrome mouse model

SCOPE: Down syndrome (DS), caused by trisomy of human chromosome 21 (Hsa21), is characterized by a spectrum of phenotypes including skeletal abnormalities. The Ts65Dn DS mouse model exhibits similar skeletal phenotypes as humans with DS. DYRK1A, a kinase encoded on Hsa21, has been linked to deficiencies in bone homeostasis in DS mice and individuals with DS. Treatment with Epigallocatechin-3-gallate (EGCG), a known inhibitor of Dyrk1a, improves some skeletal abnormalities associated with DS in mice. EGCG supplements are widely available but the effectiveness of different EGCG-containing supplements has not been well studied. METHODS AND RESULTS: Six commercially available supplements containing EGCG were analyzed, and two of these supplements were compared with pure EGCG for their impact on skeletal deficits in a DS mouse model. The results demonstrate differential effects of commercial supplements on correcting skeletal abnormalities in Ts65Dn mice. Different EGCG-containing supplements display differences in degradation, polyphenol content, and effects on trisomic bone. CONCLUSION: This work suggests that the dose of EGCG and composition of EGCG-containing supplements may be important in correcting skeletal deficits associated with DS. Careful analyses of these parameters may lead to a better understanding of how to improve skeletal and other deficits that impair individuals with DS

Mechanism of Pion Production in alphaalphap Scattering at 1 GeV/nucleon

The one-pion and two-pion production in the p(alpha, alpha prime)X reaction at an energy of E{alpha} = 4.2 GeV has been studied by simultaneous registration of the scattered alpha particles and the secondary pion or proton. The obtained results demonstrate that the inelastic alpha-particle scattering on the proton at the energy of the experiment proceeds either through excitation and decay of Delta resonance in the projectile or through excitation in the target proton of the Roper resonance, which decays mainly on a nucleon and a pion or a nucleon and a sigma meson - system of two pions in the isospin I = 0, S-wave.Comment: 16 pages, 10 figures. Submitted to Proceedings of the XX International Baldin Seminar on High - Energy Physics Problems, Dubna, October 4 - 9, 201

Multi-scale environmental filters and niche partitioning govern the distributions of riparian vegetation guilds

Across landscapes, riparian plant communities assemble under varying levels of disturbance, environmental stress, and resource availability, leading to the development of distinct riparian life-history guilds over evolutionary timescales. Identifying the environmental filters that exert selective pressures on specific riparian vegetation guilds is a critical step in setting baseline expectations for how riparian vegetation may respond to environmental conditions anticipated under future global change scenarios. In this study, we ask: (1) What riparian plant guilds exist across the interior Columbia and upper Missouri River basins? (2) What environmental filters shape riparian guild distributions? (3) How does resource partitioning among guilds influence guild distributions and co-occurrence? Woody species composition was measured at 703 stream reaches and each species\u27 morphological and functional attributes were extracted from a database in four categories: (1) life form, (2) persistence and growth, (3) reproduction, and (4) resource use. We clustered species into guilds by morphological characteristics and attributes related to environmental tolerances, modeling these guilds\u27 distributions as a function of environmental filters-regional climate, watershed hydrogeomorphic characteristics, and stream channel form- and guild coexistence. We identified five guilds: (1) a tall, deeply rooted, long-lived, evergreen tree guild, (2) a xeric, disturbance tolerant shrub guild, (3) a hydrophytic, thicket-forming shrub guild, (4) a low-statured, shadetolerant, understory shrub guild, and (5) a flood tolerant, mesoriparian shrub guild. Guilds were most strongly discriminated by species\u27 rooting depth, canopy height and potential to resprout and grow following biomass-removing disturbance (e.g., flooding, fire). Hydro-climatic variables, including precipitation, watershed area, water table depth, and channel form attributes reflective of hydrologic regime, were predictors of guilds whose life history strategies had affinity or aversion to flooding, drought, and fluvial disturbance. Biotic interactions excluded guilds with divergent life history strategies and/or allowed for the co-occurrence of guilds that partition resources differently in the same environment. We conclude that the riparian guild framework provides insight into how disturbance and bioclimatic gradients shape riparian functional plant diversity across heterogeneous landscapes. Multiple environmental filters should be considered when the riparian response guild framework is to be used as a decisionsupport tool framework across large spatial extents. Copyright: © 2015 Hough-Snee et al

Ascidians at the Pacific and Atlantic entrances to the Panama Canal

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aquatic Invasions 6 (2011): 371-380, doi:10.3391/ai.2011.6.4.02.The Panama Canal region is susceptible to non-native species introductions due to the heavy international shipping traffic through the area. Ascidian introductions are occurring worldwide but little is known about introductions at the Panama Canal. Surveys were conducted in 2002, 2008, and 2009 within the Pacific and Atlantic entrances to the canal. We found a high diversity of ascidians on both sides of the canal, dominated by non-native species; six species occurred at both Pacific and Atlantic Panama sites. This is the first report of Polyandrocarpa anguinea and P. sagamiensis in Atlantic Panama waters and Ascidia incrassata, Ascidia sydneiensis, Botrylloides nigrum, Botryllus planus, Didemnum perlucidum, Diplosoma listerianum, Microcosmus exasperatus, Polyandrocarpa zorritensis, Polyclinum constellatum, Symplegma brakenhielmi, Symplegma rubra, and Trididemnum orbiculatum in Pacific Panama waters. The canal may serve as a major invasion corridor for ascidians and should be monitored over time.Funding for this project came from WHOI Ocean Life Institute-Tropical Research Initiative to Carman and CNPq to Rocha

Testing an Intentional Naming Scheme Using Genetic Algorithms

Abstract. Various attempts have been made to use genetic algorithms (GAs) for software testing, a problem that consumes a large amount of time and eort in software development. We demonstrate the use of GAs in automating testing of complex data structures and methods for manipulating them, which to our knowledge has not been successfully displayed before on non-trivial software structures. We evaluate the ef-fectiveness of our GA-based test suite generation technique by applying it to test the design and implementation of the Intentional Naming Sys-tem (INS), a new scheme for resource discovery and service location in a dynamic networked environment. Our analysis using GAs reveals serious problems with both the design of INS and its inventors ' implementation.

CP Violation in Hyperon Nonleptonic Decays within the Standard Model

We calculate the CP-violating asymmetries A(Lambda_-^0) and A(Xi_-^-) in nonleptonic hyperon decay within the Standard Model using the framework of heavy-baryon chiral perturbation theory (chiPT). We identify those terms that correspond to previous calculations and discover several errors in the existing literature. We present a new result for the lowest-order (in chiPT) contribution of the penguin operator to these asymmetries, as well as an estimate for the uncertainty of our result that is based on the calculation of the leading nonanalytic corrections.Comment: 21 pages, 2 figures; discussion clarified, results & conclusions unchanged, to appear in Phys. Rev.