124 research outputs found

    Experts, Conflicts of Interest, and the Controversial Role of Reputation

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    This paper studies the impact of reputation on the reporting strategy of experts that face conflicts of interest. The framework we propose applies to different settings involv- ing decision makers that rely on experts for making informed decisions, such as financial analysts and goverment agencies. We show that reputation has a non-monotonic effect on the degree of information revelation. In general, truthful revelation is more likely to occur when there is more uncertainty on an expert's ability. Furthermore, above a certain threshold, an increase in reputation always makes truthful revelation more difficult to achieve. Our results shed light on the relationship between the institutional features of the reporting environment and informational efficiency.

    The Open Data Kit suite, Mobile Data Collection technology as an opportunity for forest mensuration practices

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    This paper examines the potential for using Mobile Data Collection (MDC) as an effective database supported technology to substantially improve forest mensuration practices. Open source Open Data Kit (ODK) procedures and tools were used during a survey campaign that initiated a local forest monitoring process in the Marganai forest (Sardinia). The ODK suite is practical to use and its procedures allow authoring and use of digital survey forms without users needing software development expertise. Form design enables a high degree of customization to be achieved by means of specifying a wide range of data flow control mechanisms. ODK has proved to be a valid tool for data coherence and completeness improvements. As forestry’s contribution to regional Gross Domestic Product has dramatically decreased, forest mensuration practices have been reduced. Meeting the increased need to monitor environmental assets such as forests requires these practices to be re-evaluated. If regional public institutions took an active part in the process of enhancing forest mensuration, by contributing with open database systems acting as repositories and knowledge engines, support for MDC tools like ODK would potentially be a great opportunity to disseminate the use of the system and boost its development

    Observations on different post-fire bio-engineering interventions and vegetation response in a Pinus canariensis C. Sm. forest

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    On the Canary Islands, during the 2007 (30 July - 2 August) wildfire, about 18.000 hectares of forest were destroyed. After the event, to avoid erosion, a series of mixed check dams (wooden elements and stones with a core filled with forest residues) were built in the gullies created by the surface runoff. This first study aims to investigate the different responses of vegetation and its recovery after fire, with three different types of structures. We analyzed the performance and evolution of the mixed check dams nine years after their construction and the post-fire response of vegetation with the different types of bio-engineering techniques applied. The effects of the mixed check dams are expressed in terms of plant density, frequency, and cover both in absolute and in relative terms and the same effects were compared with those of the rocks, check dams, wattle fences, and structure in the surrounding areas. Our observations show that fire adaptation in the Canary Islands vegetation (pyrophyte plants), coupled with selected bio-engineering techniques, facilitated resprouting, seeds germination and a quick restoration of the forest ecosystem. The study confirms that simple, nature-based and low cost bio-engineering measures, which use local materials and are consistent with traditional building experiences effectively contribute to site restoration

    Temporal Dynamics of Root Reinforcement in European Spruce Forests

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    The quantification of post-disturbance root reinforcement (RR) recovery dynamics is of paramount importance for the optimisation of forest ecosystem services and natural hazards risk management in mountain regions. In this work we analyse the long-term root reinforcement dynamic of spruce forests combining data of the Swiss National Forest Inventory with data on root distribution and root mechanical properties. The results show that root reinforcement recovery depends primarily on stand altitude and slope inclination. The maximum root reinforcement recovery rate is reached at circa 100 years. RR increases continuously with different rates for stand ages over 200 years. These results shows that RR in spruce stands varies considerably depending on the local conditions and that its recovery after disturbances requires decades. The new method applied in this study allowed for the first time to quantify the long term dynamics of RR in spruce stands supporting new quantitative approaches for the analysis of shallow landslides disposition in different disturbance regimes of forests

    Forest Protection Unifies, Silviculture Divides: A Sociological Analysis of Local Stakeholders' Voices after Coppicing in the Marganai Forest (Sardinia, Italy)

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    Today, a forest is also understood as a real social actor with multiple-scale influences, capable of significantly conditioning the social, economic, and cultural system of a whole territory. The aim of this paper is to reconstruct and interpret the population's perception of the silvicultural activities related to traditional use of forest resources of the southwestern Sardinian Marganai State Forest. The "Marganai case" has brought to the attention of the mass media the role of this forest and its silviculture. The research was carried out via semi-structured interviews with the main stakeholders in the area. The qualitative approach in the collection and analysis of the information gathered has allowed us to reconstruct the historical-cultural and social cohesion function that the forest plays in rural communities. The results highlight that the main risks concern the erosion of the cultural forest heritage due to the abandonment of the rural dimension (mainly by the new generations, but not only), with the consequent spread of deep distortions in the perception, interpretation, and necessity of forestry activities and policy

    A fully photonics-based coherent radar system

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    The next generation of radar (radio detection and ranging) systems needs to be based on software-defined radio to adapt to variable environments, with higher carrier frequencies for smaller antennas and broadened bandwidth for increased resolution. Today's digital microwave components (synthesizers and analogue-to-digital converters) suffer from limited bandwidth with high noise at increasing frequencies, so that fully digital radar systems can work up to only a few gigahertz, and noisy analogue up- and downconversions are necessary for higher frequencies. In contrast, photonics provide high precision and ultrawide bandwidth, allowing both the flexible generation of extremely stable radio-frequency signals with arbitrary waveforms up to millimetre waves, and the detection of such signals and their precise direct digitization without downconversion. Until now, the photonics-based generation and detection of radio-frequency signals have been studied separately and have not been tested in a radar system. Here we present the development and the field trial results of a fully photonics-based coherent radar demonstrator carried out within the project PHODIR. The proposed architecture exploits a single pulsed laser for generating tunable radar signals and receiving their echoes, avoiding radio-frequency up- and downconversion and guaranteeing both the software-defined approach and high resolution. Its performance exceeds state-of-the-art electronics at carrier frequencies above two gigahertz, and the detection of non-cooperating aeroplanes confirms the effectiveness and expected precision of the system

    Observation And Modeling Of Inner Divertor Re-attachment In Discharges With Lithium Coatings in NSTX

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    In the National Spherical Torus Experiment (NSTX), modifications to the inner divertor plasma regimes are observed in high triangularity, H-mode, NBI heated discharges due to lithium coatings evaporated on the plasma facing components. In particular, the drop in the recombination rate, the reduced neutral pressure and the reduced electron density (inferred from Stark broadening measurements of high−n deuterium Balmer lines) suggested that the inner divertor, which is usually detached in discharges without lithium, re-attached. Experimental results are compared to simulations obtained with a 1D partially ionized plasma transport model integrated in the non-local thermodynamic equilibrium radiation transport code CRETIN to understand how the reduced recycling affects the divertor parameters in NSTX discharges with lithium coatings

    Mitigation of plasma-wall interactions with low-Z powders in DIII-D high confinement plasmas

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    Experiments with low-Z powder injection in DIII-D high confinement discharges demonstrated increased divertor dissipation and detachment while maintaining good core energy confinement. Lithium (Li), boron (B), and boron nitride (BN) powders were injected in high-confinement mode plasmas (Ip=I_p=1 MA, Bt=B_t=2 T, PNB=P_{NB}=6 MW, ⟨ne⟩=3.6−5.0⋅1019\langle n_e\rangle=3.6-5.0\cdot10^{19} m−3^{-3}) into the upper small-angle slot (SAS) divertor for 2-s intervals at constant rates of 3-204 mg/s. The multi-species BN powders at a rate of 54 mg/s showed the most substantial increase in divertor neutral compression by more than an order of magnitude and lasting detachment with minor degradation of the stored magnetic energy WmhdW_{mhd} by 5%. Rates of 204 mg/s of boron nitride powder further reduce ELM-fluxes on the divertor but also cause a drop in confinement performance by 24% due to the onset of an n=2n=2 tearing mode. The application of powders also showed a substantial improvement of wall conditions manifesting in reduced wall fueling source and intrinsic carbon and oxygen content in response to the cumulative injection of non-recycling materials. The results suggest that low-Z powder injection, including mixed element compounds, is a promising new core-edge compatible technique that simultaneously enables divertor detachment and improves wall conditions during high confinement operation
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