7 research outputs found
High-quality polarization entanglement state preparation and manipulation in standard telecommunication channels
We report a novel and simple approach for generating near-perfect quality
polarization entanglement in a fully guided-wave fashion. Both deterministic
pair separation into two adjacent telecommunication channels and the paired
photons' temporal walk-off compensation are achieved using standard fiber
components. Two-photon interference experiments are performed, both for
quantitatively demonstrating the relevance of our approach, and for
manipulating the produced state between bosonic and fermionic symmetries. The
compactness, versatility, and reliability of this configuration makes it a
potential candidate for quantum communication applications.Comment: 6 figure
Productivitatea clonelor de plop hibrid instalate în culturi intensive în nord-estul României [ Poplar clones productivity managed for biomass production in North-Eastern Romania]
Poplar (Populus spp.) is a fast-growing species in temperate conditions,
with potential to substitute fossil fuels by obtaining energy from
biomass. The aim of this work was to study the productivity of 6 hybrid
poplar clone from a hilly region of NE Romania, after a growing season of
4 and, respectively, 5 years. Rods were used as planting material, planted
at a density of 2667 trees per ha, with between-row spacing of 3 m and
interior-row distances of 1.25 m. Generally, significant differences appear
between clones, for all analysed biometric characteristics (p≤0.05). Results
show that, in the fifth growing season, diameter increases on average with
15.1%, reaching 11.89 cm, height increases in average with 13.9%, reaching
11.89 m, and volume increases with 33.3%, reaching 0.172 m3. The total
biomass after 4 years vegetation varies from 32.8 t/ha to 39.4 t/ha, and after
5 years from 47.7 t/ha to 60.2 t/ha, having an average increase in the latest
growing season of 35% and an average yield of 11.3 t/ha/year. The most productive
clones in the given growing conditions and crop characteristics are
the clone Pannonia after 4 growing seasons and the clone AF6 after 5 years
Ungulate browsing causes species loss in deciduous forests independent of community dynamics and silvicultural management in Central and Southeastern Europe
Grid-based inventories of 1,924 deciduous forests plots in Germany and 4,775 in Romania were used to investigate tree species composition as affected by browsing and grazing under different forest management (rotation forestry, selectively cut forest, protected forest). At regional scale, the loss of tree species in the dominant layer was between 52 to 67% in Germany and of 10 to 30% in Romania, with largest effects in protected nature reserves in Germany. At plot level, only 50% (Germany) to 54% (Romania) of canopy species were found in the regeneration layer with a height of 1.5 m. Browsing was influenced by the proportion of Fagus in the regenerating trees in Germany, and by stand density, basal area, and management in both regions. Structural equation modeling explained 11 to 26% of the variance in species loss based on the fresh loss of the terminal bud in the winter prior to the inventory work (one season browsing). Browsing (and grazing in Romania) is shown to be a significant cause of species loss across both countries and all management types. Potential cascading effects on other organisms of deciduous forest ecosystems are discussed. We conclude that the present hunting practices that support overabundant ungulate populations constitute a major threat to the biodiversity of deciduous forests in Germany and Romania and to other places with similar ungulate management, and that changes my only be possible by modernizing the legal framework of hunting