6,042 research outputs found

    Rethinking False Spring Risk

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    Temperate plants are at risk of being exposed to late spring freezes. These freeze events - often called false springs - are one of the strongest factors determining temperate plants species range limits and can impose high ecological and economic damage. As climate change may alter the prevalence and severity of false springs, our ability to forecast such events has become more critical, and it has led to a growing body of research. Many false spring studies largely simplify the myriad complexities involved in assessing false spring risks and damage. While these studies have helped advance the field and may provide useful estimates at large scales, studies at the individual to community levels must integrate more complexity for accurate predictions of plant damage from late spring freezes. Here we review current metrics of false spring, and how, when and where plants are most at risk of freeze damage. We highlight how life stage, functional group, species differences in morphology and phenology, and regional climatic differences contribute to the damage potential of false springs. More studies aimed at understanding relationships among species tolerance and avoidance strategies, climatic regimes, and the environmental cues that underlie spring phenology would improve predictions at all biological levels. An integrated approach to assessing past and future spring freeze damage would provide novel insights into fundamental plant biology, and offer more robust predictions as climate change progresses, which is essential for mitigating the adverse ecological and economic effects of false springs

    Simulation of carbon cycling, including dissolved organic carbon transport, in forest soil locally enriched with 14C

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    The DyDOC model was used to simulate the soil carbon cycle of a deciduous forest at the Oak Ridge Reservation (Tennessee, USA). The model application relied on extensive data from the Enriched Background Isotope Study (EBIS), which exploited a short-term local atmospheric enrichment of radiocarbon to establish a large-scale manipulation experiment with different inputs of 14C from both above-ground and below-ground litter. The model was first fitted to hydrological data, then observed pools and fluxes of carbon and 14C data were used to fit parameters describing metabolic transformations of soil organic matter (SOM) components and the transport and sorption of dissolved organic matter (DOM). This produced a detailed quantitative description of soil C cycling in the three horizons (O, A, B) of the soil profile. According to the parameterised model, SOM turnover within the thin O-horizon rapidly produces DOM (46 gC m-2 a-1), which is predominantly hydrophobic. This DOM is nearly all adsorbed in the A- and B-horizons, and while most is mineralised relatively quickly, 11 gC m-2 a-1 undergoes a “maturing” reaction, producing mineral-associated stable SOM pools with mean residence times of 100-200 years. Only a small flux (~ 1 gC m-2 a-1) of hydrophilic DOM leaves the B-horizon. The SOM not associated with mineral matter is assumed to be derived from root litter, and turns over quite quickly (mean residence time 20-30 years). Although DyDOC was successfully fitted to C pools, annual fluxes and 14C data, it accounted less well for short-term variations in DOC concentrations

    The hearing of fitness to practice cases by the General Medical Council: Current trends and future research agendas

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    Over the last three decades a risk-based model of medical regulation has emerged in the United Kingdom. To promote a risk-averse operational culture of transparency and professional accountability the regulatory state has intervened in medical governance and introduced best-evidenced practice frameworks, audit and performance appraisal, Against this background the paper analyses descriptive statistical data pertaining to the General Medical Council’s management of the process by which fitness to practice complaints against doctors are dealt with from initial receipt through to subsequent investigative and adjudication stages. Statistical trends are outlined regarding complaint data in relation to a doctor’s gender and race and ethnicity. The data shows that there has been an increase in rehabilitative and/or punitive action against doctors. In light of its findings the paper considers what the long-term consequences may be, for both patients and doctors, of the increasing use of risk-averse administrative systems to reform medical regulation and ensure professional accountability

    Ciao AI: the Italian adaptation and validation of the Chatbot Usability Scale

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    Chatbot-based tools are becoming pervasive in multiple domains from commercial websites to rehabilitation applications. Only recently, an eleven-item satisfaction inventory was developed (the ChatBot Usability Scale, BUS-11) to help designers in the assessment process of their systems. The BUS-11 has been validated in multiple contexts and languages, i.e., English, German, Dutch, and Spanish. This scale forms a solid platform enabling designers to rapidly assess chatbots both during and after the design process. The present work aims to adapt and validate the BUS-11 inventory in Italian. A total of 1360 questionnaires were collected which related to a total of 10 Italian chatbot-based systems using the BUS-11 inventory and also using the lite version of the Usability Metrics for User eXperience for convergent validity purposes. The Italian version of the BUS-11 was adapted in terms of the wording of one item, and a Multi-Group Confirmatory Factorial Analysis was performed to establish the factorial structure of the scale and compare the effects of the wording adaptation. Results indicate that the adapted Italian version of the scale matches the expected factorial structure of the original scale. The Italian BUS-11 is highly reliable (Cronbach alpha: 0.921), and it correlates to other measures of satisfaction (e.g., UMUX-Lite, τb = 0.67; p < .001) by also offering specific insights regarding the chatbots’ characteristics. The Italian BUS-11 can be confidently used by chatbot designers to assess the satisfaction of their users during formative or summative tests

    The benefits of organic farming for biodiversity

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    Previous studies suggest widespread positive responses of biodiversity to organic farming. Many of these studies, however, have been small-scale. This project tested the generality of habitat and biodiversity differences between matched pairs of organic and non-organic farms containing cereal crops in lowland England on a large-scale across a range of taxa including plants, insects, birds and bats. The extent of both cropped and un-cropped habitats together with their composition and management on a range of scales were also compared. Organic farms was likely to favour higher levels of biodiversity and indeed organic farms tended to support higher numbers of species and overall abundance across most taxa. However, the magnitude of the response differed strikingly; plants showed stronger and more consistent responses than other taxa. Some, but not all, differences in biodiversity between systems appear to be a consequence of differences in habitat quantity

    Resonant hyper-Raman scattering in spherical quantum dots

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    A theoretical model of resonant hyper-Raman scattering by an ensemble of spherical semiconductor quantum dots has been developed. The electronic intermediate states are described as Wannier-Mott excitons in the framework of the envelope function approximation. The optical polar vibrational modes of the nanocrystallites (vibrons) and their interaction with the electronic system are analized with the help of a continuum model satisfying both the mechanical and electrostatic matching conditions at the interface. An explicit expression for the hyper-Raman scattering efficiency is derived, which is valid for incident two-photon energy close to the exciton resonances. The dipole selection rules for optical transitions and Fr\"ohlich-like exciton-lattice interaction are derived: It is shown that only exciton states with total angular momentum L=0,1L=0,1 and vibrational modes with angular momentum lp=1l_p=1 contribute to the hyper-Raman scattering process. The associated exciton energies, wavefunctions, and vibron frequencies have been obtained for spherical CdSe zincblende-type nanocrystals, and the corresponding hyper-Raman scattering spectrum and resonance profile are calculated. Their dependence on the dot radius and the influence of the size distribution on them are also discussed.Comment: 12 pages REVTeX (two columns), 2 tables, 8 figure
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