141 research outputs found

    Characterization of low loss microstrip resonators as a building block for circuit QED in a 3D waveguide

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    Here we present the microwave characterization of microstrip resonators made from aluminum and niobium inside a 3D microwave waveguide. In the low temperature, low power limit internal quality factors of up to one million were reached. We found a good agreement to models predicting conductive losses and losses to two level systems for increasing temperature. The setup presented here is appealing for testing materials and structures, as it is free of wire bonds and offers a well controlled microwave environment. In combination with transmon qubits, these resonators serve as a building block for a novel circuit QED architecture inside a rectangular waveguide

    Small-scale grassland assembly patterns differ above and below the soil surface

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    Contains fulltext : 103764.pdf (publisher's version ) (Open Access

    TRY plant trait database - enhanced coverage and open access

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    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Shotgun metagenomic sequencing for conservation genomics: rock ptarmigan as a case study

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    The rock ptarmigan (Lagopus muta) inhabits alpine and arctic tundra throughout the northern hemisphere with its current distribution mainly determined by the last glacial maximum. In southern Europe this species is only found in fragmented populations on the main mountain ranges, where numbers are decreasing due to habitat loss, degradation and fragmentation, climate warming and human disturbance. This decline could be mitigated through conservation measures, but these require fundamental information on the evolutionary ecology, distribution and genetic diversity. Such data is difficult to collect in a species which is particularly elusive and living in extreme environments. Thanks to the technological and computational advances of recent years, understanding of species’ biology has been greatly enhanced by analyzing fecal samples, collected non-invasively in the field, using shotgun metagenomics sequencing. Although this approach is still poorly tested in wild species, ongoing studies highlight its potential for conservation and biomonitoring that should be further explored. In the present study, this approach was applied to 30 rock ptarmigan from three different areas of the Paneveggio-Pale di San Martino Natural Park, characterized by contrasting rocky substrates. The shotgun metagenomic sequencing method does not require the enrichment or targeted amplification of specific molecular markers, thus allowing both qualitative and quantitative evaluation of data on different aspects related to the species. In particular, the ongoing analyses aimed to determine: i) the genomic relationships between individuals and population, ii) the fundamental resources for the species through the study of the diet, iii) the health status of individuals through the analysis of gut microbiota and parasites. First results confirmed the utility of shotgun metagenomic sequencing for conservation purposes and provides fundamental data for improving conservation strategies for this species

    Effects of twenty years of ungulate browsing on forest regeneration at Paneveggio Reserve, Italy

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    Forest ecosystems are threatened by different natural disturbances. Among them, the irruption of large herbivores represents one of the most alarming issues. Several local-scale studies have been carried out to clarify the mechanisms governing ungulate\u2013forest interactions, to understand the effect of wild ungulates overabundance, and to apply conservation plans. However, information at large scales, over long periods of observation and from unmanipulated conditions is still scarce. This study aims to improve our knowledge in this field by using repeated inventories to investigate: the types of damage produced by ungulate populations on young trees, the drivers that stimulate browsing activity and its consequences on the specific composition of seedlings and saplings. To reach these goals, we used data collected during a twenty-year monitoring program (1994\u20132014) in the forests of Paneveggio-Pale di San Martino Nature Park (Italy). We applied descriptive statistics to summarize the data, GLMs to identify the drivers of browsing activity and Non-Metric Multidimensional Scaling (nMDS) ordinations to investigate the changes in specific composition of young trees across 20 years. We detected increasing browsing activity from 1994 to 2008 and a decline in 2014. Ungulates browsed preferentially in mature stands, and fed mostly on seedlings and saplings under 150 cm of height. The analysis of the environmental drivers of browsing pressure on the smallest size classes of plants suggests that foraging behavior is influenced by snowpack conditions, ungulate density and seasonality. Moreover, results underline the fact that ungulates feed mostly on palatable species, especially European rowan, but can also use unpalatable plants as emergency food under high competition levels. nMDS results suggest that rowan seed dispersion might be promoted by deer movements, however, saplings of this species were not able to exceed 30 cm of height because of heavy browsing. This bottleneck effect led to the dominance of unpalatable species, mostly Norway spruce, reducing diversity during forest regeneration. If prolonged, this effect could lead to a reduction of tree species richness, with cascading effects on many parts of the ecosystem, and threatening the resilience of the forest to future disturbances
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