3,713 research outputs found

    Restoring soil functionality in degraded areas of organic vineyards - Preliminary results of the ReSolVe project in the French vineyards

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    Degraded soil areas in vineyards are associated with problems in vine health, grape production and quality. Different causes for soil degradation are possible such as poor organic matter content, lower plant nutrient availability, pH, water deficiency, soil compaction / lower oxygenation
 The aim of this preliminary study is to assess soil functionality (OM decomposition), biodiversity through mesofauna diversity and consequences for vine growth and quality

    Tourism income and economic growth in Greece: Empirical evidence from their cyclical components

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    This paper examines the relationship between the cyclical components of Greek GDP and international tourism income for Greece for the period 1976–2004. Using spectral analysis the authors find that cyclical fluctuations of GDP have a length of about nine years and that international tourism income has a cycle of about seven years. The volatility of tourism income is more than eight times the volatility of the Greek GDP cycle. VAR analysis shows that the cyclical component of tourism income is significantly influencing the cyclical component of GDP in Greece. The findings support the tourism-led economic growth hypothesis and are of particular interest and importance to policy makers, financial analysts and investors dealing with the Greek tourism industry

    Contribution of forbidden orbits in the photoabsorption spectra of atoms and molecules in a magnetic field

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    In a previous work [Phys. Rev. A \textbf{66}, 0134XX (2002)] we noted a partial disagreement between quantum R-matrix and semiclassical calculations of photoabsorption spectra of molecules in a magnetic field. We show this disagreement is due to a non-vanishing contribution of processes which are forbidden according to the usual semiclassical formalism. Formulas to include these processes are obtained by using a refined stationary phase approximation. The resulting higher order in ℏ\hbar contributions also account for previously unexplained ``recurrences without closed-orbits''. Quantum and semiclassical photoabsorption spectra for Rydberg atoms and molecules in a magnetic field are calculated and compared to assess the validity of the first-order forbidden orbit contributions.Comment: 12 pages, 6 figure

    Novel approaches to investigating spatial variability in channel bank total phosphorus at the catchment scale

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    Phosphorus (P) is often a limiting nutrient that leads to the eutrophication of aquatic systems. While dissolved P forms are the most bioavailable, the form, mobility, transport and fate of P are directly related to its association with fine-grained riverine sediment. Therefore, to implement successful P catchment management strategies it is important to understand the relative contribution of different sediment sources to P loads across the river continuum. While agricultural topsoil and, to a lesser extent, riverbed sediment are important sources of sediment-associated P, channel banks have been shown to be an important sediment source in some catchments. However, comparatively little is known about the P concentration and corresponding spatial variability in channel bank sediment and the associated implications for catchment management. The present study examines the spatial variability of P associated with channel bank profiles within a series of three nested catchments using both non-spatial and spatial statistical methods, where for the latter, a novel spatial approach was used to estimate the spatial averages and variances of P in channel bank sediment along the stream network. Channel bank P concentrations were compared to factors such as catchment scale, stream order, land use, bank exposure and location along the stream network. Concentrations of TP ranged between 129.6 and 1206.9 mg P kg⁻Âč of which the water extractable P (WEP) content ranged from 0.01 to 0.12%. Stream order was found to influence TP concentrations, while land use and catchment scale provided only a moderate influence. This suggested that focussing channel bank sampling strategies at the largest catchment scale would capture key drivers of TP variability provided stream order is sufficiently represented. Whether the bank was had limited vegetation and was exposed and potentially eroding had a slight influence on TP variability in second-order stream banks in the larger of the two nested catchments. However, the slightly lower TP concentrations measured at these sites indicated that banks that are actually eroding may be contributing less TP than the total channel bank TP values measured across the catchments as a whole. The results of an explicitly spatial analysis demonstrated that local channel bank TP averages and TP variances vary along the stream network. Specifically, the most accurate spatial predictor of TP was local TP means with the use of ‘crow flies’ rather than stream network distances. Local TP variances were used to provide optimal designs for future channel bank TP sampling campaigns, given available resources. Throughout, both standard and outlier-resistant statistical analyses were applied to improve interpretation of the study findings

    Current advisory interventions for grazing ruminant farming cannot close exceedance of modern background sediment loss – Assessment using an instrumented farm platform and modelled scaling out

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    Water quality impairment by elevated sediment loss is a pervasive problem for global water resources. Sediment management targets identify exceedance or the sediment loss ‘gap’ requiring mitigation. In the UK, palaeo-limnological reconstruction of sediment loss during the 100–150 years pre-dating the post-World War II intensification of agriculture, has identified management targets (0.20−0.35 t ha−1 yr−1) representing ‘modern background sediment delivery to rivers’. To assess exceedance on land for grazing ruminant farming, an integrated approach combined new mechanistic evidence from a heavily-instrumented experimental farm platform and a scaling out framework of modelled commercial grazing ruminant farms in similar environmental settings. Monitoring (2012–2016) on the instrumented farm platform returned sediment loss ranges of 0.11−0.14 t ha−1 yr−1 and 0.21−0.25 t ha−1 yr-1 on permanent pasture, compared with between 0.19−0.23 t ha−1 yr-1 and 0.43−0.50 t ha−1 yr−1and 0.10−0.13 t ha−1 yr−1and 0.25−0.30 t ha−1 yr-1 on pasture with scheduled plough and reseeds. Excess sediment loss existed on all three farm platform treatments but was more extensive on the two treatments with scheduled plough and reseeds. Excessive sediment loss from land used by grazing ruminant farming more strategically across England, was estimated to be up to >0.2 t ha−1 yr−1. Modelled scenarios of alternative farming futures, based on either increased uptake of interventions typically recommended by visual farm audits, or interventions selected using new mechanistic understanding for sediment loss from the instrumented farm platform, returned minimum sediment loss reductions. On the farm platform these were 2.1 % (up to 0.007 t ha−1 yr−1) and 5.1 % (up to 0.018 t ha−1 yr-1). More strategically, these were up to 2.8 % (0.014 t ha−1 yr−1) and 4.1 % (0.023 t ha−1 yr−1). Conventional on-farm measures will therefore not fully mitigate the sediment loss gap, meaning that more severe land cover change is required

    Quels enjeux pour la gestion des eaux urbaines ? Contribution Ă  la formulation des services attendus par le systĂšme de gestion des eaux urbaines

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    International audienceLe systĂšme d'assainissement dont nous hĂ©ritons s'est dĂ©veloppĂ© en couches successives, rĂ©pondant chacune Ă  des enjeux diffĂ©rents, et qui prĂ©sentent une valeur patrimoniale trĂšs importante. Ces systĂšmes doivent aujourd'hui rĂ©pondre Ă  des enjeux de plus en plus diversifiĂ©s. Les techniques mises en Âœuvre deviennent Ă©galement de plus en plus diversifiĂ©es. Cette multiplication des fonctions et des dispositifs concourt Ă  accroĂźtre le nombre d'organisations concernĂ©es et actives dans la gestion du systĂšme. Se pose alors la question de la coordination d'une pluralitĂ© d'organisations, gĂ©rant une pluralitĂ© d'ouvrages dans une grande diversitĂ© d'objectifs et d'intĂ©rĂȘts. L'enjeu principal devient donc le dĂ©veloppement d'un systĂšme durable de gestion des eaux urbaines qui se compose de dispositifs techniques et spatiaux, d'organisations en charge de ces dispositifs, et du bassin versant naturel correspondant au domaine d'influence. Cependant, pour gĂ©rer ce systĂšme, il faut dans un premier temps identifier les enjeux liĂ©s aux eaux urbaines. La multiplication des dispositifs et organisations, et le changement d'Ă©chelle pour considĂ©rer le systĂšme (ville + bassin versant naturel) nĂ©cessite en effet de repenser les services qu'il doit rendre. Cette communication propose une rĂ©ponse sous forme de " marguerite des fonctions ". Les fonctions de service liĂ©es Ă  la gestion des eaux urbaines et le mode d'obtention de la marguerite sont dĂ©taillĂ©s

    Aesthetic response to color combinations: preference, harmony, and similarity

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    Previous studies of preference for and harmony of color combinations have produced confusing results. For example, some claim that harmony increases with hue similarity, whereas others claim that it decreases. We argue that such confusions are resolved by distinguishing among three types of judgments about color pairs: (1) preference for the pair as a whole, (2) harmony of the pair as a whole, and (3) preference for its figural color when viewed against its colored background. Empirical support for this distinction shows that pair preference and harmony both increase as hue similarity increases, but preference relies more strongly on component color preference and lightness contrast. Although pairs with highly contrastive hues are generally judged to be neither preferable nor harmonious, figural color preference ratings increase as hue contrast with the background increases. The present results thus refine and clarify some of the best-known and most contentious claims of color theorists

    Development of an international standard set of outcome measures for patients with atrial fibrillation: a report of the International Consortium for Health Outcomes Measurement (ICHOM) atrial fibrillation working group.

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    AIMS: As health systems around the world increasingly look to measure and improve the value of care that they provide to patients, being able to measure the outcomes that matter most to patients is vital. To support the shift towards value-based health care in atrial fibrillation (AF), the International Consortium for Health Outcomes Measurement (ICHOM) assembled an international Working Group (WG) of 30 volunteers, including health professionals and patient representatives to develop a standardized minimum set of outcomes for benchmarking care delivery in clinical settings. METHODS AND RESULTS: Using an online-modified Delphi process, outcomes important to patients and health professionals were selected and categorized into (i) long-term consequences of disease outcomes, (ii) complications of treatment outcomes, and (iii) patient-reported outcomes. The WG identified demographic and clinical variables for use as case-mix risk adjusters. These included baseline demographics, comorbidities, cognitive function, date of diagnosis, disease duration, medications prescribed and AF procedures, as well as smoking, body mass index (BMI), alcohol intake, and physical activity. Where appropriate, and for ease of implementation, standardization of outcomes and case-mix variables was achieved using ICD codes. The standard set underwent an open review process in which over 80% of patients surveyed agreed with the outcomes captured by the standard set. CONCLUSION: Implementation of these consensus recommendations could help institutions to monitor, compare and improve the quality and delivery of chronic AF care. Their consistent definition and collection, using ICD codes where applicable, could also broaden the implementation of more patient-centric clinical outcomes research in AF

    Structure of boson systems beyond the mean-field

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    We investigate systems of identical bosons with the focus on two-body correlations. We use the hyperspherical adiabatic method and a decomposition of the wave function in two-body amplitudes. An analytic parametrization is used for the adiabatic effective radial potential. We discuss the structure of a condensate for arbitrary scattering length. Stability and time scales for various decay processes are estimated. The previously predicted Efimov-like states are found to be very narrow. We discuss the validity conditions and formal connections between the zero- and finite-range mean-field approximations, Faddeev-Yakubovskii formulation, Jastrow ansatz, and the present method. We compare numerical results from present work with mean-field calculations and discuss qualitatively the connection with measurements.Comment: 26 pages, 6 figures, submitted to J. Phys. B. Ver. 2 is 28 pages with modified figures and discussion
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