28 research outputs found

    Were there significant changes in the overall condition of the CONECOFOR plots over the 1995 -2005 period?

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    Since 1995 the CONECOFOR programme is collecting data on a number of attributes of forest ecosystems in 20 permanent plots in Italy. In this paper, different multivariate methods were used to detect possible changes and deviations in the overall biological and chemical-physical status of the CONECOFOR plots as compared to defined reference periods. The reference periods were set-up taking into account the data availability and were as follows: 1997-1999 for biological status; 1999-2002 for chemical-physical status. Changes of the biological conditions of the plots were identified only in a few cases over the period 2000 - 2004 and were due to low values in transparency and basal area increment of the intermediate and dominated layer. On the other hand, several changes were detected in relation to the chemical and physical status over the period 2003-2005. Some few regularities were identified: (i) change/deviations concentrated on few plots; (ii) high ozone (O3), low sulphur deposition and low precipitation were the attributes more consistently related tochanges/deviations; (iii) most deviations were due to changes in the correlation structure of the attributes; and (iv) there is no consistenttiming of change/deviations among plots. These findings emphasise the need to evaluate the data at the plot level and this indicate the importance of obtaining a time series long enough to enable plot-wise integrated analysis

    Simulation of an experimental database of infrared spectra of complex gaseous mixtures for detecting specific substances. The case of drug precursors

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    This work is motivated by the need to develop suitable databases in absence of real experimental data, for instance when spectra measured with a newly developed instrumentation on real samples are not available yet. This notwithstanding, in fact, the realization of the physical project should be addressed by a starting database, also invaluable in order to test its effectiveness. In this article we face the issue of simulating gas mixtures spectra for the development of a new sensor for External Cavity-Quantum Cascade Laser Photoacoustic Spectroscopy (EC-QCLPAS) starting from literature FT-IR spectra of pure components: a dataset is realized suitable to realistically represent the ensemble of spectra of the gas mixtures of interest. The informative data deriving from the literature spectra were combined with the stochastic component extracted from a sample spectrum recorded with a prototype instrument, allowing us to build a matrix containing thousands of simulated spectra of gaseous mixtures, accounting for the presence of different components at different concentrations. Signal processing and experimental design techniques were used along the whole path leading to the dataset of simulated spectra. In particular, the goal of the construction of the database lies in the development of a final system to detect drug precursors in the vapour phase. The comparison of some EC-QCLPAS spectra with the corresponding simulated signals confirms the validity of the proposed approach

    A feature selection strategy for the analysis of spectra from a photoacoustic sensing system

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    In the frame of the EU project CUSTOM, a new sensor system for the detection of drug precursors in gaseous samples is being developed, which also includes an External Cavity-Quantum Cascade Laser Photo Acoustic Sensor (ECQCLPAS). In order to define the characteristics of the laser source, the optimal wavenumbers within the most effective 200 cm -1 range in the mid-infrared region must be identified, in order to lead to optimal detection of the drug precursor molecules in presence of interfering species and of variable composition of the surrounding atmosphere. To this aim, based on simulations made with FT-IR spectra taken from literature, a complex multivariate analysis strategy has been developed to select the optimal wavenumbers. Firstly, the synergistic use of Experimental Design and of Signal Processing techniques led to a dataset of 5000 simulated spectra of mixtures of 33 different gases (including the 4 target molecules). After a preselection, devoted to disregard noisy regions due to small interfering molecules, the simulated mixtures were then used to select the optimal wavenumber range, by maximizing the classification efficiency, as estimated by Partial Least Squares - Discriminant Analysis. A moving window 200 cm -1 wide was used for this purpose. Finally, the optimal wavenumber values were identified within the selected range, using a feature selection approach based on Genetic Algorithms and on resampling. The work made will be relatively easily turned to the spectra actually recorded with the newly developed EC-QCLPAS instrument. Furthermore, the proposed approach allows progressive adaptation of the spectral dataset to real situations, even accounting for specific, different environments

    Status and change of tree crown condition at the CONECOFOR plots, 1996 - 2005

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    Between 1996 and 2005 crown condition at Italian Level II plots was assessed annually within the CONECOFOR programme. Three different assessment forms and manuals were adopted over this period of time (the first in 1996-97, the second between 1998 and 2004, the last starting in 2005); as a result, many of the parameters investigated and the data collected are neither homogeneous nor comparable over time. Since, however, neither the definition nor the assessment criteria for transparency changed, this parameter was chosen to represent crown condition variations over time. (In this survey, transparency is used as a proxy for defoliation.) Yearly field surveys were always preceded by an inter-calibration course, and were followed up by Quality Control surveys done by one or more Reference Teams. After 10 years, the results suggest that statistically significant variations in transparency, from one year to the next, are only scattered and display no recognizable trend. Overall, there were 15 variations, of which 7 were positive (i.e. increase in transparency), and 8 negative (i.e. decrease in transparency). The majority of variations is concentrated in the 1997-98 period. Significant defoliation trends were identified in 11 out of the 27 considered plots. In 4 cases these trends were positive (increased transparency)

    Metabolomic Profile of Young Adults Born Preterm

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    Prematurity is a risk factor for the development of chronic adult diseases. Metabolomics can correlate the biochemical changes to a determined phenotype, obtaining real information about the state of health of a subject at that precise moment. Significative differences in the metabolomic profile of preterm newborns compared to those born at term have been already identified at birth. An observational case–control study was performed at the University Hospital of Siena. The aim was to evaluate and compare the metabolomic profiles of young adults born preterm to those born at term. Urinary samples were collected from 67 young adults (18–23 years old) born preterm (mean gestational age of 30 weeks, n = 49), and at term of pregnancy (mean gestational age of 38 weeks, n = 18). The urinary spectra of young adults born preterm was different from those born at term and resembled what was previously described at birth. The Random Forest algorithm gave the best classification (accuracy 82%) and indicated the following metabolites as responsible for the classification: citrate, CH2 creatinine, fumarate and hippurate. Urine spectra are promising tools for the early identification of neonates at risk of disease in adulthood and may provide insight into the pathogenesis and effects of fetal programming and infants’ outcomes

    Creatine Transporter Defect Diagnosed by Proton NMR Spectroscopy in Males With Intellectual Disability

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    Creatine deficiency syndrome due to mutations in X-linked SLC6A8 gene results in nonspecific intellectual disability (ID). Diagnosis cannot be established on clinical grounds and is often based on the assessment of brain creatine levels by magnetic resonance spectroscopy (MRS). Considering high costs of MRS and necessity of sedation, this technique cannot be used as a first level-screening test. Likewise, gene test analysis is time consuming and not easily accessible to all laboratories. In this article feasibility of urine analysis (creatine/creatinine (Cr/Crn) ratio) performed by nuclear magnetic resonance (NMR) as a first level-screening test is explored. Before running a systematic selection of cases a preliminary study for further molecular analysis is shown. NMR urine spectra (n = 1,347) of male patients with an ID without a clinically recognizable syndrome were measured. On the basis of abnormal Cr/Crn ratio, three patients with the highest values were selected for molecular analysis. A confirmatory second urine test was positive in two patients and diagnosis was further confirmed by a decreased brain creatine level and by SLC6A8 gene analysis. A de novo mutation was identified in one. Another patient inherited a novel mutation from the mother who also has a mild ID. A repeat urine test was negative in the third patient and accordingly creatine level in the brain and SLC6A8 gene analysis both gave a normal result. We conclude that Cr/Crn ratio measured by NMR for male patients represents a rapid and useful first level screening test preceding molecular analysis. © 2011 Wiley-Liss, Inc

    Estrogen-like activity of seafood related to environmental chemical contaminants

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    BACKGROUND: A wide variety of environmental pollutants occur in surface waters, including estuarine and marine waters. Many of these contaminants are recognised as endocrine disrupting chemicals (EDCs) which can adversely affect the male and female reproductive system by binding the estrogen receptor and exhibiting hormone-like activities. In this study the estrogenic activity of extracts of edible marine organisms for human consumption from the Mediterranean Sea was assayed. METHODS: Marine organisms were collected in two different areas of the Mediterranean Sea. The estrogenic activity of tissues was assessed using an in vitro yeast reporter gene assay (S. cerevisiae RMY 326 ER-ERE). Concentrations of polychlorinated biphenyls (PCBs) (congeners 28, 52, 101, 118, 138, 153, 180) in fish tissue was also evaluated. RESULTS: Thirty-eight percent of extracts showed a hormone-like activity higher than 10% of the activity elicited by 10 nM 17b-estradiol (E2) used as control. Total PCB concentrations ranged from 0.002 up to 1.785 ng/g wet weight. Chemical analyses detected different levels of contamination among the species collected in the two areas, with the ones collected in the Adriatic Sea showing concentrations significantly higher than those collected in the Tyrrhenian Sea (p < 0.01). CONCLUSION: The more frequent combination of chemicals in the samples that showed higher estrogenic activity was PCB 28, PCB 101, PCB 153, PCB 180. The content of PCBs and estrogenic activity did not reveal any significant correlation

    Tree canopy defoliation can reveal growth decline in mid-latitude temperate forests

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    Climate and weather fluctuations and changes are the most important environmental driver of tree canopy defoliation, an indicator of forest health. We examined the relationship between tree defoliation and Basal Area Increment (BAI), a dimension of tree growth related to wood biomass increment, carbon sequestration and therefore to the climate change mitigation potential of forests. We analysed data from mostly even-aged, single-species permanent monitoring plots in France over two growing periods (1995-2004: 47 plots, 2008 trees; 2000-2009: 63 plots, 3116 trees) and for which precipitation deficit was identified as the main environmental driver of defoliation. Trees from ten different species were assessed annually for defoliation and measured periodically for growth, from which we derived periodical (10-year) BAI (BAIperiod). We investigated (i) direction and significance of defoliation-BAIperiod relationship and (ii) occurrence, size and significance of BAI deviation of progressively defoliated trees in proportion to the BAI of undefoliated trees (BAIrel). Analyses were first carried out at the level of individual plots, with results subsequently evaluated using meta-analysis, and further aggregated at different levels (all species, functional groups, individual species). BAIperiod resulted negatively and significantly related to defoliation, with a significant reduction detected already at slight (15%) defoliation level. A generalized statistically significant reduction of BAIrel was obvious, leading to an estimated reduction of 0.7 - 0.8% per unit increase of defoliation for conifers, and 0.9% for broadleaves. Considering the observed distribution of trees along the defoliation range, our results indicate an overall growth reduction of ca. 42% in comparison to a theoretical population of undefoliated trees. Shifts in such a distribution can result into loss or gains of growth, which in turn may have cascading effects on carbon sequestration and therefore on land-climate interactions. In the context of the significant increase in defoliation observed in Europe in recent decades, our results suggest that even slight and moderate variations in defoliation may have had a significant impact on tree and forest growth

    Status and trend of tree growth and mortality rate at the CONECOFOR plots, 1997-2004

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    The circumference of trees in the CONECOFOR permanent monitoring plots (PMPs) were measured by three surveys carried out in 1997, 2000 and 2005. Plots were arranged into forest types according to tree species, management system and stand structure: beech (Fagus sylvatica L.) and spruce (Picea abies K.) high forests, aged coppice forests and transitory crops (deciduous, evergreen oaks and beech). Diameter distribution, basal area, basal area increment, tree mortality rate and in-growth were calculated per layer (dominant, intermediate, dominated) within each PMP, to point out relative contributions and changes. A range in relative annual growth was detected both within and between types over the monitored period, but an obvious reduction of annual increment was found in two/thirds of plots over 2000-04 as compared to 1997-99. Current mortality, mostly allocated into the dominated and intermediate layers, can be explained as “regular” due to overstocking and high inter-tree competition in almost all of the observed case-studies. Opposite patterns were found to occur as for stand growth vs. mortality rate between coppice forests and the other types owing to the different dynamics of tree competition in progress. Drought 2003 is the likely large-scale factor determining the reduced annual growth course over the second period.</p
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