Mass vegetative propagation of Ostrya carpinifolia by continual removal of axillary branches from juvenile donor plants

The propagation of ornamental standard trees by seedlings or traditional cutting methods does not allow to obtain a juvenile plants with a high degree of homogeneity. Vegetative propagation by microcutting may be a solution to attain this object. This technique is based on the construction of juvenile donor plants through frequent and regular pruning of young plants. Our experiment involved one arborescent species, Ostrya carpinifolia, using one unpruned control and two types of pruning treatments, in relation with the number of internodes of axis bearing the cuttings. The treatment with axis constituted of four internodes gave the best results, with 147 cuttings after 143 days of growing of donor plants and 83% of rooting, after 21 days of cutting. For this species, vegetative propagation using juvenile donor plants with pruning to two internodes is highly satisfactory. Therefore, this vegetative propagation by juvenile donor plant can be proposed to produce homogeneous standard tree

Nonlinear Polariton Fluids in a Flatband Reveal Discrete Gap Solitons

Phase frustration in periodic lattices is responsible for the formation of dispersionless flat bands. The absence of any kinetic energy scale makes flat band physics critically sensitive to perturbations and interactions. We report here on the experimental investigation of the nonlinear dynamics of cavity polaritons in the gapped flat band of a one-dimensional Lieb lattice. We observe the formation of gap solitons with quantized size and very abrupt edges, signature of the frozen propagation of switching fronts. This type of gap solitons belongs to the class of truncated Bloch waves, and had only been observed in closed systems up to now. Here the driven-dissipative character of the system gives rise to a complex multistability of the nonlinear domains generated in the flat band. These results open up interesting perspective regarding more complex 2D lattices and the generation of correlated photon phases.Comment: 6 pages, 4 figures + supplemental material (6 pages, 6 figures

Unstable and stable regimes of polariton condensation

Modulational instabilities play a key role in a wide range of nonlinear optical phenomena, leading e.g. to the formation of spatial and temporal solitons, rogue waves and chaotic dynamics. Here we experimentally demonstrate the existence of a modulational instability in condensates of cavity polaritons, arising from the strong coupling of cavity photons with quantum well excitons. For this purpose we investigate the spatiotemporal coherence properties of polariton condensates in GaAs-based microcavities under continuous-wave pumping. The chaotic behavior of the instability results in a strongly reduced spatial and temporal coherence and a significantly inhomogeneous density. Additionally we show how the instability can be tamed by introducing a periodic potential so that condensation occurs into negative mass states, leading to largely improved coherence and homogeneity. These results pave the way to the exploration of long-range order in dissipative quantum fluids of light within a controlled platform.Comment: 7 pages, 5 figure

The Influence of Pruning on Morphological and Architectural Characteristics of Camellia japonica L. in a Tropical Climate

The ornamental qualities of Camellia japonica have long been of interest to horticulturists. The European garden plant market has traditionally been characterized by erect, branched and flowered plants. More recently, a new market linked to increasing urbanization has developed for compact, highly branched and flowered plants to decorate balconies and patios. Two flushes are formed per year in temperate climates, and three years are required to obtain a garden plant. In the humid, tropical climate of Reunion Island, at an altitude of 700 m, three to four flushes are formed in a single growing season. Under these conditions and with no pruning, it is possible to produce an upright plant with a height of 48.5 cm and 7.5 branchings, adapted to the traditional garden market. With two prunings and the same growing period, a compact plant with a height of 25.4 and 17.0 branchings can be produced, adapted to the new balcony-patio market. In both cases, floral induction occurs in November when the nighttime temperature is above 15 degrees C. This research shows that it is possible to generate diversified and innovative forms of Camellia japonica with considerable marketing potential using adapted pruning and under appropriate climatic conditions

From publishers to self-publishing: disruptive effects in the book industry

This paper explores the structure of the book publishing industry post digitalisation, analysing the choices of the publishers and authors. The introduction of successful e-book readers has belatedly given digitalisation the characteristics of a disruptive technology by making self-publishing a serious option for authors. This has been supported by the entry of new types of intermediaries and the strengthening of others. These changes have reduced the general requirements for an author to get a book self-published. As a result, a larger share of the surplus from the book industry is likely to go to authors, explaining the significant increase in the supply of books. The potential oversupply of books has created a new problem by increasing competition and making consumer searches more difficult. We argue that digitalisation has shifted the potential for market failure from an inadequate supply of books to asymmetric information about quality. It remains to be seen whether the market will provide appropriate intermediaries to solve the asymmetric information problem