490 research outputs found

    DOES CBD THEORY SURVIVE THE TEST OF SMALL CITIES? CITY-SIZE AND SPRAWL IN ITALY

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    Abstract Economic theory predicts that the equilibrium of different economic forces explains the spatial scale of a city more than the uncontrolled take of agricultural land, which is considered instead as urban sprawl. A wide range of empirical results based on US data for large urban areas supports this hypothesis, showing that the socio-economic and environmental forces explain a vast portion of the variation in urbanization across cities. In this paper, we ask whether these socio-economic forces are relevant also in small cities and if they are in a different manner, provided that sprawling phenomena may occur more easily in small areas due to the larger availability of agricultural land. To answer the question, we estimate the relationship between city size and the socio-economic and environmental forces using data for small and large municipalities in the Lombardy region, Italy, and test to what extent this model is apt to explain size variations. We find that the model is adequate also in the case of small cities but differentiating small from large cities suggests that the sprawl hypothesis cannot be ruled out by the empirical evidence as the process of land conversion from agricultural to urban is substantially faster in small and medium-sized cities compared to large ones

    Undoped and Fe-Doped Anatase/Brookite TiO2 Mixed Phases, Obtained by a Simple Template-Free Synthesis Method: Physico-Chemical Characterization and Photocatalytic Activity towards Simazine Degradation

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    For the first time, Fe-doping (0.05, 1.0, and 2.5 wt.% Fe) was performed on a high-surface-area anatase/brookite TiO2 by adopting a simple template-free sol-gel synthesis followed by calcination at a mild temperature. The powders’ textural and surface properties were characterized by following a multi-technique approach. XRD analysis showed that the anatase/brookite ratio slightly varied in the Fe-doped TiO2 (from 76.9/23.1 to 79.3/22.7); Fe doping noticeably affected the cell volume of the brookite phase, which decreased, likely due to Fe3+ ions occupying interstitial positions, and retarded the crystallite growth. N2 sorption at −196 °C showed the occurrence of samples with disordered interparticle mesopores, with an increase in the specific surface area from 236 m2 g−1 (undoped TiO2) to 263 m2 g−1 (2.5 wt.% Fe). Diffuse Reflectance UV-Vis spectroscopy showed a progressive decrease in the bandgap energy from 3.10 eV (undoped TiO2) to 2.85 eV (2.5 wt.% Fe). XPS analysis showed the presence of some surface Fe species only at 2.5 wt.% Fe, and accordingly, the ζ-potential measurements showed small changes in the pH at the isoelectric point. The photocatalytic degradation of simazine (a persistent water contaminant) both under UV and simulated solar light was performed as a probe reaction. Under UV light, Fe-doping improved simazine degradation in the sample at 0.05 wt.% Fe, capable of degrading ca. 77% simazine. Interestingly, the undoped TiO2 was also active both under UV and 1 SUN. This is likely due to the occurrence of anatase/brookite heterojunctions, which help stabilize the photogenerated electrons/holes

    Ambipolar suppression of superconductivity by ionic gating in optimally-doped BaFe2(As,P)2 ultrathin films

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    Superconductivity (SC) in the Ba-122 family of iron-based compounds can be controlled by aliovalent or isovalent substitutions, applied external pressure, and strain, the combined effects of which are sometimes studied within the same sample. Most often, the result is limited to a shift of the SC dome to different doping values. In a few cases, the maximum SC transition at optimal doping can also be enhanced. In this work, we study the combination of charge doping together with isovalent P substitution and strain by performing ionic gating experiments on BaFe2_2(As0.8_{0.8}P0.2_{0.2})2_2 ultrathin films. We show that the polarization of the ionic gate induces modulations to the normal-state transport properties that can be mainly ascribed to surface charge doping. We demonstrate that ionic gating can only shift the system away from the optimal conditions, as the SC transition temperature is suppressed by both electron and hole doping. We also observe a broadening of the resistive transition, which suggests that the SC order parameter is modulated nonhomogeneously across the film thickness, in contrast with earlier reports on charge-doped standard BCS superconductors and cuprates.Comment: 10 pages, 5 figure

    Governance fragmentation and urban spatial expansion: Evidence from Europe and the United States

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    This study assesses the effects of urban governance structure on the spatial expansion of metropolitan areas. A more fragmented governance structure, represented by a high number of administrative units with decision power on land use per inhabitant, is expected to increase the competition between small towns in the suburbs of metropolitan areas to attract households and workers, which, in turn, induces more land uptake. We study empirically the relationship between administrative fragmentation and the spatial size of cities in a sample of 180 metropolitan areas in the contexts of the US and Europe in the period 2000-2012. Results shed light on the structural differences between the two broad regions and suggest that administrative fragmentation impacts positively on land uptake in both the United States and Europe, although to different extents

    What is the prevalence, and what are the clinical correlates, of insulin resistance in young people presenting for mental health care? A cross-sectional study

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    Objectives: To report the distribution and predictors of insulin resistance (IR) in young people presenting to primary care-based mental health services. Design: Cross-sectional. Setting: Headspace-linked clinics operated by the Brain and Mind Centre of the University of Sydney. Participants: 768 young people (66% female, mean age 19.7±3.5, range 12–30 years). Main outcome measures: IR was estimated using the updated homeostatic model assessment (HOMA2-IR). Height and weight were collected from direct measurement or self-report for body mass index (BMI). Results: For BMI, 20.6% of the cohort were overweight and 10.2% were obese. However,6.9 mmol/L). By contrast, 9.9% had a HOMA2-IR score \u3e2.0 (suggesting development of IR) and 11.7% (n=90) had a score between 1.5 and 2. Further, there was a positive correlation between BMI and HOMA2-IR (r=0.44, p Conclusions: Emerging IR is evident in a significant subgroup of young people presenting to primary care based mental health services. While the major modifiable risk factor is BMI, a large proportion of the variance is not accounted for by other demographic, clinical or treatment factors. Given the early emergence of IR, secondary prevention interventions may need to commence prior to the development of full-threshold or major mood or psychotic disorders

    genetic diversity and relationship among the three autochthonous sicilian donkey populations assessed by microsatellite markers

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    AbstractIn the developed countries donkey has lost its main function as draft animal because of the mechanization in agri-culture; as a consequence donkey population was greatly reduced. According to SAVE monitoring institute, three of the eight Italian endangered donkey breeds are native of Sicily (Ragusano, Pantesco, Grigio Siciliano). Urgent safeguard plans are required. The aim of this work is to investigate the distribution of genetic diversity and the relationships among the three Sicilian autochthonous donkey breeds using a set of microsatellite markers. A total of 116 blood samples (61 Ragusano, 39 Pantesco, 16 Grigio Siciliano) were collected in 9 herds all over Sicily. Representative samples of Ragusano and Grigio donkey populations consist of unrelated individuals, whereas the sample of Pantesco represents nearly the entire studbook-registered population managed by "Ispettorato Ripartimentale delle Foreste di Erice (TP)" in the "Azienda S. Matteo". Genomic DNA was amplified at 11 microsatellite..

    An Empirical Approach to Integrating Climate Reputational Risk in Long-Term Scenario Analysis

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    We propose an empirical approach to estimate the impact of climate transition risk on corporate revenues that specifically accounts for reputational risk. We employ the information on disclosed Scope 3 emissions to proxy companies' carbon footprint along the value chain. A threshold regression is employed to identify the emission level above which reputational risk impacts revenues, and we link this impact to a climate policy stringency indicator. We estimate the threshold regression on a sample of companies within the European Union (EU), and find the threshold at around the 70th percentile of the Scope 3 emissions distribution. We find that companies with Scope 3 emissions beyond the threshold experienced substantially lower revenue growth as climate policies have become more stringent, compared to other companies

    Hepatic Resection Using a Water Jet Dissector

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    The mortality and morbidity in major hepatic resection is often related to hemorrhage. A high pressure, high velocity water jet has been developed and has been utilized to assist in hepatic parenchymal transection. Sixty-seven major hepatic resections were performed for solid hepatic tumors. The tissue fracture technique was used in 51 patients (76%), and the water jet dissector was used predominantly in 16 patients (24%). The extent of hepatic resection using each technique was similar. The results showed no difference in operative duration (p = .499). The mean estimated blood loss using the water jet was 1386 ml, and tissue fracture technique 2450 ml (p = .217). Transfusion requirements were less in the water jet group (mean 2.0 units) compared to the tissue fracture group (mean 5.2 units); (p = .023). Results obtained with the new water dissector are encouraging. The preliminary results suggest that blood loss may be diminished

    The evolution of farm size : an exploratory study by configural frequency analysis

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    Investment support measures in agriculture can have differentiated effects on the strategic reorganisation and the performance of farms. In this paper, we study the patterns of technical change of a sample of farms in the Lombardy region, Italy, that invested in structural modernisation benefiting from the financial incentives provided under the measure 121. We find evidence relating the modernisation of farms under the umbrella of the measure 121 to limited positive changes in farmland and more substantial positive changes in other inputs. The results are not conclusive regarding a causal relationship between the measure 121 and the structural change of farms. Nonetheless, the paper describes a situation in which patterns of farmland reduction are relatively less frequent in farms that make use of this policy instrument

    Urban sprawl and air quality in European Cities: an empirical assessment

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    In this paper we estimate the relationship between urban sprawl and a measure of air quality, namely the number of days in which the PM10 concentration exceeds safeguard limits in European Union cities. Building on a multidimensional representation of sprawl, the paper employs several indicators to account for built-up area development, population density, and residential discontinuity. The paper employs generalised additive models to disentangle the non-linear effects in the variables and the interaction effects of the three sprawl dimensions. A significant and robust effect of urban morphology emerges after controlling for socio-economic, demographic, and climatic factors and the geographical location of the city. We find that urban sprawl impacts positively on pollutant concentration, but the effect is highly context-specific because of threshold effects and interactions
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