50 research outputs found

    Influenze ambientali sull'accrescimento radiale nella quercia da sughero

    Get PDF
    The purpose of this study is to contribute to the knowledge of the effects of the climatic trends on the cork oak system and to furnish a base of prediction models related to the wood growth. The area of the study is located in the centre of Sardinia. The area covers an overall surface of 9 Km2 for the statistic analysis and of 25 Km2 for the simulation. We have collected the measures of trees with diameter at breast height between 15 and 30 cm. The statistic analysis has concerned: 1) the classification of the statistic variables; 2) the treatment of the satellite images MODIS for the extraction of space- temporal variables related to temperatures at ground level, the water content and the mass vegetation; 3) the definition of the samples with a high possibility of error; 4) Annealing simulation for the optimization of the model and of data. Finally we have create one prediction model for a vast area. The Pearson correlation of show that the average increases of a sample group of trees are tightly tied to thermometric trend. The analysis with geo-statistics technique has brought to verify that there is a clear correlation with the content of water, with the daytime temperature, and with the biomass. While the increases, on the other hand, are negatively correlated with the night-temperatures and the EVI. The results of the simulations have brought, finally, to the possibility to build prediction maps with annual, biennial and cumulative scale

    Population Saturation in Trivalent Erbium Sensitized by Organic Molecular Antennae

    Get PDF
    We investigate sensitization efficiency of near-infrared emission and population saturation of trivalent erbium in erbium quincilinolato complexes photoexcited into the absorption band of the organic sensitizer. At low excitation levels, we find high (similar to 80%) sensitization efficiencies. We observe excited state population saturation at inversion threshold under subnanosecond pumping at the level of one injected photoexcitation per complex

    Local landscape dynamics in a traditional cork-oak agro-forest system (Sardinia)

    Get PDF
    The Alta Gallura region contributed to the development of Italian cork industry that since the nineteenth century has driven the improvement of a multi-functional model based on the breeding of beef cattle into the cork oak forests. The study case is a cork-oak agro-forest farm extended to 212 hectares, with a quantity of livestock close to 0.1 LU ha-1. It were collected data from the farm registry (business records of the last 70 years) and by photo-interpretation of images related to 1955 (GAI), 1977 (CGR), 2006 (Terra Italy) and 2013 (AGEA)

    skin reaction in antiviral therapy for chronic hepatitis c a role for polyethylene glycol interferon

    Get PDF
    In the past decade, different modalities of antiviral therapy have been adopted aimed at eradicating hepatitis C virus infection. Initially, interferon was used in monotherapy, then interferon combined with ribavirin and amantadine. Recently, interferon has been conjugated with polyethylene glycol to allow optimization of its pharmacokinetic properties and to improve its antiviral activity. This study focused on the characteristics of the skin reactions that we observed in 27 patients with naive hepatitis C who received polyethylene glycol interferon-ribavirin-amantadine or polyethylene glycol interferon-ribavirin and in 10 previous non-responders to interferon monotherapy who were retreated with triple therapy. In 9 patients (7 on triple therapy) dermatitis-like lesions were observed, and in 5 the severity of the lesions necessitated withdrawal from therapy

    Interaction of the N-(3-Methylpyridin-2-yl)amide Derivatives of Flurbiprofen and Ibuprofen with FAAH: Enantiomeric Selectivity and Binding Mode

    Get PDF
    Background Combined fatty acid amide hydrolase (FAAH) and cyclooxygenase (COX) inhibition is a promising approach for pain-relief. The Flu-AM1 and Ibu-AM5 derivatives of flurbiprofen and ibuprofen retain similar COX-inhibitory properties and are more potent inhibitors of FAAH than the parent compounds. However, little is known as to the nature of their interaction with FAAH, or to the importance of their chirality. This has been explored here. Methodology/Principal Findings FAAH inhibitory activity was measured in rat brain homogenates and in lysates expressing either wild-type or FAAHT488A-mutated enzyme. Molecular modelling was undertaken using both docking and molecular dynamics. The (R)- and (S)-enantiomers of Flu-AM1 inhibited rat FAAH with similar potencies (IC50 values of 0.74 and 0.99 ÎĽM, respectively), whereas the (S)-enantiomer of Ibu-AM5 (IC50 0.59 ÎĽM) was more potent than the (R)-enantiomer (IC50 5.7 ÎĽM). Multiple inhibition experiments indicated that both (R)-Flu-AM1 and (S)-Ibu-AM5 inhibited FAAH in a manner mutually exclusive to carprofen. Computational studies indicated that the binding site for the Flu-AM1 and Ibu-AM5 enantiomers was located between the acyl chain binding channel and the membrane access channel, in a site overlapping the carprofen binding site, and showed a binding mode in line with that proposed for carprofen and other non-covalent ligands. The potency of (R)-Flu-AM1 was lower towards lysates expressing FAAH mutated at the proposed carprofen binding area than in lysates expressing wild-type FAAH. Conclusions/Significance The study provides kinetic and structural evidence that the enantiomers of Flu-AM1 and Ibu-AM5 bind in the substrate channel of FAAH. This information will be useful in aiding the design of novel dual-action FAAH: COX inhibitors

    Anatomy of a portfolio optimizer under a limited budget constraint

    No full text
    Predicting the market's behavior to profit from trading stocks is far from trivial. Such a task becomes even harder when investors do not have large amounts of money available, and thus cannot influence this complex system in any way. Machine learning paradigms have been already applied to financial forecasting, but usually with no restrictions on the size of the investor's budget. In this paper, we analyze an evolutionary portfolio optimizer for the management of limited budgets, dissecting each part of the framework, discussing in detail the issues and the motivations that led to the final choices. Expected returns are modeled resorting to artificial neural networks trained on past market data, and the portfolio composition is chosen by approximating the solution to a multi-objective constrained problem. An investment simulator is eventually used to measure the portfolio performance. The proposed approach is tested on real-world data from New York's, Milan's and Paris' stock exchanges, exploiting data from June 2011 to May 2014 to train the framework, and data from June 2014 to July 2015 to validate it. Experimental results demonstrate that the presented tool is able to obtain a more than satisfying profit for the considered time fram

    Portfolio Optimization, a Decision-Support Methodology for Small Budgets

    No full text
    Several machine learning paradigms have been applied to financial forecasting, attempting to predict the market's behavior, with the final objective of profiting from trading shares. While anticipating the performance of such a complex system is far from trivial, this issue becomes even harder when the investors do not have large amounts of money available. In this paper, we present an evolutionary portfolio optimizer for the management of small budgets. The expected returns are modeled resorting to Multi-layer Perceptrons, trained on past market data, and the portfolio composition is chosen by approximating the solution to a multi-objective constrained problem. An investment simulator is then used to measure the portfolio performance. The proposed approach is tested on real-world data from Milan stock exchange, exploiting information from January 2000 to June 2010 to train the framework, and data from July 2010 to August 2011 to validate it. The presented tool is finally proven able to obtain a more than satisfying profit for the considered time fram

    Employing a spatio-temporal contingency table for the analysis of cork oak cover change in the Sa Serra region of Sardinia

    No full text
    Land cover change analyses are common and, especially in the absence of explanatory variables, they are mainly carried out by employing qualitative methods such as transition matrices or raster operations. These methods do not provide any estimation of the statistical significance of the changes, or the uncertainty of the model and data, and are usually limited in supporting explicit biological/ecological interpretation of the processes determining the changes. Here we show how the original nearest-neighbour contingency table, proposed by Dixon to evaluate spatial segregation, has been extended to the temporal domain to map the intensity, statistical significance and uncertainty of land cover changes. This index was then employed to quantify the changes in cork oak forest cover between 1998 and 2016 in the Sa Serra region of Sardinia (Italy). The method showed that most statistically significant cork oak losses were concentrated in the centre of Sa Serra and characterised by high intensity. A spatial binomial-logit generalised linear model estimated the probability of changes occurring in the area but not the type of change. We show how the spatio-temporal Dixon’s index can be an attractive alternative to other land cover change analysis methods, since it provides a robust statistical framework and facilitates direct biological/ecological interpretation

    Hematological malignancies in the island of Sardinia, 1974-1993: age and sex distributions and temporal changes in incidence

    No full text
    We have collected, by an active retrospective survey, all the cases of hematologic malignancies (HM) newly diagnosed during the time period 1974–1993 in the resident population of Sardinia. Diagnosis was deemed valid, after consultation of clinical records, in more than 90% of the 7264 collected cases. The number of newly diagnosed cases by year more than doubled during the 20-year period investigated. This striking increase can be only partially accounted for by ageing of population. Indeed, age-specific and age-adjusted rates of most of HM increased during this period, although Hodgkin Disease (HD), Chronic Myeloid Leukemia (CML) and Acute Lymphoblastic Leukemia (ALL) were notable exceptions. The observed increase in rates is likely, in a large part, to be fictitious, due to easier access to a health care system, which in the meantime, improved its diagnostic efficiency. This was particularly evident for Chronic Lymphocytic Leukemia (CLL), Multiple Myeloma (MM) and some others myelo- and lympho-proliferative disorders, but its relevance declined after 1984–1989. A likely true increase in occurrence was evidenced for Non-Hodgkin Lymphomas (NHL) and similarly, although to a lesser extent and more doubtful, for Myelodysplasias (MDS) and Acute Myeloid Leukemia (AML). At the end of the studied period each type of HM presented age and sex distributions and ageadjusted rates that show only minor differences from those reported for other western countries. No argument emerged to suggest that any genetic peculiarities of the Sardinian population might have affected the occurrence of HM. The confounding effects of improved diagnostic efficiency have prevented a reliable assessment of influence on incidences of environmental and socio-economic changes that, in relatively recent times, have occurred in Sardinia

    Ultrafast dynamics of intersystem crossing and resonance energy transfer in Er(III)-quinolinolate complexes

    No full text
    Organocomplexes with trivalent erbium are investigated by time-resolved optical spectroscopy techniques. Ultrafast time scales are reported for intraligand intersystem crossing (similar to 10 ps) and ligand-to-metal resonance energy transfer (similar to 100 ps), resulting in lanthanide-ion sensitization with nearly unity efficiency. Given the interest of erbium complexes for telecom wavelength solid-state amplifiers and emitters, the results should stimulate further theoretical investigations on radiationless transitions in such complexes
    corecore