Phenology of fynbos, renosterveld and subtropical thicket in the south eastern Cape

Qualitative and quantitative phenological observations were made on 173 species in eight communities in climatically similar sites. Results indicated that in species growing on different substrates, soil type had a minimal effect on phenophases. Phenophase patterns were analyzed by grouping species into growth form classes. Geophytes and annuals grew from autumn to spring. The majority of restioids and C3 grasses grew most in the cool wet seasons. C4 grass species showed either a summer growth season or an additional cooler growth season; the former species do not occur westwards in the winter rainfall region while the latter do. Most succulents grew in autumn and spring while two species also grew in summer. Small leaved sclerophyll shrubs grew throughout the year and/or showed a summer growth peak. The former pattern is consistent with a ‘generalist strategy’ but the latter is not readily explained because of summer drought conditions. Subtropical large leaved sclerophyll shrubs showed irregular growth and reproduction whereas large leaved proteoid shrubs grew in summer and autumn. In all shrub growth forms maximum leaf loss occurred in summer. Phenophase patterns were explained in terms of ecophysiological factors but biological and historical factors were also considered

Characterization of native hayseed: guaranteeing a seed mixture for habitat and species conservation

Here we present data on hayseed quality (purity, seed content and germination rate of seeds) for lots collected from different vegetation types and with different brush harvester types. We show that it is possible to provide labelling information with regard to hayseed quality, to calculate sowing denisties and help consumers understand the quality and performance of the product they have bought

Characterisation of brush-harvested hayseed quality (purity, seed content and germination) for the calculation of optimal sowing densities

Several projects demonstrate the utility of hayseed for ecological restoration, but how hayseed should be employed remains ambiguous as no standard procedure currently exists for hayseed characterisation. In Europe an absence of guidelines partly reflects the lack of a requirement by EC Directive 2010/60/EU for specific data quality parameters for directly harvested seed mixtures. However, the Directive states that directly harvested seed mixtures should be appropriate for restoration of each given habitat, and a density of 8000 established seedlings m-2 has been shown as a requirement for successful revegetation in alpine grasslands (Florineth 2007). We developed a method for the standardised characterisation of hayseed lots to allow labelling of recommended sowing densities for hayseed from different grassland types, inspired by the quality tests usually applied to commercial seed (such as those of the International Seed Testing Association; ISTA 2017). Hayseed was collected from 49 grassland donor sites in Lombardy, northern Italy, using three different types of brush harvester, and characterised in terms of purity (seed:inert plant material), seed content (number of seeds per unit hayseed weight) and germination capacity (density of seedlings emerging over a given area). Hayseed was also used for restoration and restored areas monitored in terms of seedling density and cover. The mean yield across all donor sites was 60.6 kg ha-1 (min./max. 19.6 to 131.8 kg ha-1). Seed content exhibited a mean of 536.5 seeds g-l, ranging from 82.4 to 2635.0 seeds g-l, and differed between brush harvester types. The mean purity across sites was 28% seed, ranging from 5 to 68%, and was also affected by brush harvester type (p<0.05). Mean germinability was 7000 seedlings m-2 (at 30d from sowing). Recent tests conducted on sub-lots of hayseed preserved for several years (3, 4 or 5), demonstrate a significant increase in germination during short term storage (germination differences in the first and fifth years for three hayseed lots): similar effects have been noted for single species of Poaceae (e.g. Shaidaee et al. 1969). During revegetation trials, complete soil cover was generally achieved after three months, associated with declining seedling density due to shifts in competitive dominance. Monitoring of sites over several years shows the progressive and spontaneous ingress of other species from surrounding vegetation, leading to floristic enrichment and development of the grassland. Optimal sowing density for each hayseed lot ranged between 5 and 94 g of hayseed per m2: values for most lots were below the sowing densities for commercial seed mixtures advised by ERSAF (2001) for establishment of vegetation for erosion control (30 to 50 g m2). Standardised characterisation of hayseed lot quality is possible in a way that allows sowing density recommendations and labelling to be carried out for each type of donor grassland

Globally Governed Session Semantics

This paper proposes a bisimulation theory based on multiparty session types where a choreography specification governs the behaviour of session typed processes and their observer. The bisimulation is defined with the observer cooperating with the observed process in order to form complete global session scenarios and usable for proving correctness of optimisations for globally coordinating threads and processes. The induced bisimulation is strictly more fine-grained than the standard session bisimulation. The difference between the governed and standard bisimulations only appears when more than two interleaved multiparty sessions exist. This distinct feature enables to reason real scenarios in the large-scale distributed system where multiple choreographic sessions need to be interleaved. The compositionality of the governed bisimilarity is proved through the soundness and completeness with respect to the governed reduction-based congruence. Finally, its usage is demonstrated by a thread transformation governed under multiple sessions in a real usecase in the large-scale cyberinfrustracture

The Nursing Worklife Model: Extending and Refining a New Theory

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75205/1/j.1365-2834.2007.00670.x.pd

Star Formation and Dynamics in the Galactic Centre

The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the vicinity of a supermassive black hole (SMBH). Despite the hostile environment, several tens of early-type stars populate the central parsec of our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The formation of such early-type stars has been a puzzle for a long time: molecular clouds should be tidally disrupted by the SMBH before they can fragment into stars. We review the main scenarios proposed to explain the formation and the dynamical evolution of the early-type stars in the GC. In particular, we discuss the most popular in situ scenarios (accretion disc fragmentation and molecular cloud disruption) and migration scenarios (star cluster inspiral and Hills mechanism). We focus on the most pressing challenges that must be faced to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A., 'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201