258 research outputs found

    Measuring the Accuracy and Precision of the Garmin GPS Positioning in Forested Areas: A Case Study in Taxiarchis-Vrastama University Forest

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    In this paper, it is attempted to examine and compare the performance of two (global positioning system) receivers of different orientation, one recreational and another more precise, in forested areas. In doing this, a field test on horizontal and vertical positional errors of GPS positioning at different points in the forested area of Taxiarchis-Vrastama University forest was conducted. The two GPS receivers were used to determine the positional accuracy of a selected number of points under tree canopies. Specifically, the precision and accuracy of Garmin’s GPS positioning at different points were calculated and compared with the corresponding positioning and accuracy of another GPS system, namely the TOPCON GPS. By the calculation of various measures of accuracy and precision suitable for GPS receivers and the use of statistical methods, accuracy between the different receivers differed significantly is shown. Also, regression analysis revealed that the basal area and the number of available satellites are the most important factors for predicting position error

    RELIABILITY CONTROL OF DIGITAL IMAGES THAT ARE USED IN FOREST INVENTORY AND MANAGEMENT IN GREECE

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    Abstract: Aim of this paper is the reliability control of digital images tha

    In situ mass spectrometry analysis of chemical vapour deposition of TiO2 thin films to study gas phase mechanisms

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    Deposition of TiO2 thin films are studied using a newly developed in situ mass spectrometry technique to observe gas phase reactions. Atmospheric pressure chemical vapour deposition (APCVD) reactions were carried out using titanium chloride and titanium tetraisopropoxide precursors, with ethyl acetate acting as an oxygen source in the case of the former, depositing on to float glass substrates at 300 and 600 Β°C. Using an atmospheric sampling mass spectrometer, the vapour phase was analysed during deposition and signals assigned to intermediate species that were measured during the formation of the thin films. The films deposited were characterised via scanning electron microscopy, X-ray photoelectron spectroscopy and thin film X-ray diffraction analysis

    Electrochemical Properties of APCVD alpha-Fe2O3 Nanoparticles at 300 degrees C

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    The growth of hematite (FeIII oxide) by atmospheric pressure chemical vapor deposition was possible at 300 oC by controlling the nitrogen flow rate through the iron precursor bubbler. An increase of crystallinity along with the presence of compact interconnected nanoparticles was observed upon increasing the nitrogen flow rate. The amount of incorporated charge was the highest for the 0.6β€…L minβˆ’1 coating presenting reversibility after a period of 1400β€…s as obtained from chronoamperometry measurements. Additionally, the charge transfer of lithium‐ions across the FeIII oxide / electrolyte interface was easier enhancing its performance presenting capacitance retention of 94 % after 500 scans. The importance of nitrogen flow rate towards the deposition of an anode with good stability and effective electrochemical behavior is highlighted

    Legacy Effect of Long-Term Elevated CO2 and Warming on Soil Properties Controls Soil Organic Matter Decomposition

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    Plant litter quality is one of the key factors that control soil organic matter (SOM) decomposition. Under climate change, although significant change in litter quality has been intensively reported, the effect of litter quality change on SOM decomposition is poorly understood. This limits our ability to model the dynamics of soil carbon under climate change. To determine the effect of litter quality and soil property change on SOM decomposition, we performed a controlled, reciprocal transplant and litter decomposition experiments. The soils and plant litters were collected from a long-term field experiment, where four treatments were designed, including: (1) the control without warming at ambient CO2; (2) elevated atmospheric CO2 up to 500 ppm (C); (3) warming plant canopy by 2 degrees C (T); (4) elevated CO2 plus warming (CT). We found that elevated CO2 and warming altered the litter quality significantly in terms of macronutrients' content and their stoichiometry. Elevated CO2 decreased the concentration of N in rice and wheat straw, while warming decreased the concentration of N and K in wheat straw. However, the change in plant litter quality did not lead to a shift in SOM decomposition. On the contrary, the legacy effect of long-term elevated CO2 and warming on soil properties dominated the decomposition rate of SOM. Elevated atmospheric CO2 suppressed SOM decomposition mainly by increasing phosphorous availability and lowering the soil C/N, fungi/bacteria ratio, and N-acetyl-glucosaminidase activity, while warming or elevated CO2 plus warming had no effect on SOM decomposition. Our results demonstrated that the changes in soil property other than litter quality control the decomposition of SOM under climate change, and soil property change in respond to climate change should be considered in model developing to predict terrestrial soil carbon dynamics under elevated atmospheric CO2 and warming

    Patients with early rheumatoid arthritis exhibit elevated autoantibody titers against mildly oxidized low-density lipoprotein and exhibit decreased activity of the lipoprotein-associated phospholipase A(2)

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    Rheumatoid arthritis is a chronic inflammatory disease, associated with an excess of cardiovascular morbidity and mortality due to accelerated atherosclerosis. Oxidized low-density lipoprotein (oxLDL), the antibodies against oxLDL and the lipoprotein-associated phospholipase A(2 )(Lp-PLA(2)) may play important roles in inflammation and atherosclerosis. We investigated the plasma levels of oxLDL and Lp-PLA(2 )activity as well as the autoantibody titers against mildly oxLDL in patients with early rheumatoid arthritis (ERA). The long-term effects of immunointervention on these parameters in patients with active disease were also determined. Fifty-eight ERA patients who met the American College of Rheumatology criteria were included in the study. Patients were treated with methotrexate and prednisone. Sixty-three apparently healthy volunteers also participated in the study and served as controls. Three different types of mildly oxLDL were prepared at the end of the lag, propagation and decomposition phases of oxidation. The serum autoantibody titers of the IgG type against all types of oxLDL were determined by an ELISA method. The plasma levels of oxLDL and the Lp-PLA(2 )activity were determined by an ELISA method and by the trichloroacetic acid precipitation procedure, respectively. At baseline, ERA patients exhibited elevated autoantibody titers against all types of mildly oxLDL as well as low activity of the total plasma Lp-PLA(2 )and the Lp-PLA(2 )associated with the high-density lipoprotein, compared with controls. Multivariate regression analysis showed that the elevated autoantibody titers towards oxLDL at the end of the decomposition phase of oxidation and the low plasma Lp-PLA(2 )activity are independently associated with ERA. After immunointervention autoantibody titers against all types of oxLDL were decreased in parallel to the increase in high-density lipoprotein-cholesterol and high-density lipoprotein-Lp-PLA(2 )activity. We conclude that elevated autoantibody titers against oxLDL at the end of the decomposition phase of oxidation and low plasma Lp-PLA(2 )activity are feature characteristics of patients with ERA, suggesting an important role of these parameters in the pathophysiology of ERA as well as in the accelerated atherosclerosis observed in these patients

    Atherogenic lipid profile is a feature characteristic of patients with early rheumatoid arthritis: effect of early treatment – a prospective, controlled study

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    We investigated lipid profiles and lipoprotein modification after immuno-intervention in patients with early rheumatoid arthritis (ERA). Fifty-eight patients with ERA who met the American College of Rheumatology (ACR) criteria were included in the study. These patients had disease durations of less than one year and had not had prior treatment for it. Smokers or patients suffering from diabetes mellitus, hypothyroidism, liver or kidney disease, Cushing's syndrome, obesity, familiar dyslipidemia and those receiving medications affecting lipid metabolism were excluded from the study. Sixty-three healthy volunteers (controls) were also included. Patients were treated with methotrexate and prednisone. Lipid profiles, disease activity for the 28 joint indices score (DAS-28) as well as ACR 50% response criteria were determined for all patients. The mean DAS-28 at disease onset was 5.8 Β± 0.9. After a year of therapy, 53 (91.3%) patients achieved the ACR 20% response criteria, while 45 (77.6%) attained the ACR 50% criteria. In addition, a significant decrease in the DAS-28, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were observed. ERA patients exhibited higher serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglycerides, whereas their serum high-density lipoprotein cholesterol (HDL-C) levels were significantly lower compared to controls. As a consequence, the atherogenic ratio of TC/HDL-C as well as that of LDL-C/HDL-C was significantly higher in ERA patients compared to controls. After treatment, a significant reduction of the atherogenic ratio of TC/HDL-C as well as that of LDL-C/HDL-C was observed, a phenomenon primarily due to the increase of serum HDL-C levels. These changes were inversely correlated with laboratory changes, especially CRP and ESR. In conclusion, ERA patients are characterized by an atherogenic lipid profile, which improves after therapy. Thus, early immuno-intervention to control disease activity may reduce the risk of the atherosclerotic process and cardiovascular events in ERA patients

    Exposure to Traffic Pollution and Increased Risk of Rheumatoid Arthritis

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    Background: Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease that affects approximately 1% of the adult population, and to date, genetic factors explain < 50% of the risk. Particulate air pollution, especially of traffic origin, has been linked to systemic inflammation in many studies. Objectives: We examined the association of distance to road, a marker of traffic pollution exposure, and incidence of RA in a prospective cohort study.Methods We studied 90,297 U.S. women in the Nurses’ Health Study. We used a geographic information system to determine distance to road at the residence in 2000 as a measure of traffic exposure. Using Cox proportional hazard models, we examined the association of distance to road and incident RA (1976–2004) with adjustment for a large number of potential confounders. Results: In models adjusted for age, calendar year, race, cigarette smoking, parity, lactation, menopausal status and hormone use, oral contraceptive use, body mass index, physical activity, and census-tract-level median income and house value, we observed an elevated risk of RA [hazard ratio (HR) = 1.31; 95% confidence interval (CI), 0.98–1.74] in women living within 50 m of a road, compared with those women living 200 m or farther away. We also observed this association in analyses among nonsmokers (HR = 1.62; 95% CI, 1.04–2.52), nonsmokers with rheumatoid factor (RF)-negative RA (HR = 1.77; 95% CI, 0.93–3.38), and nonsmokers with RF-positive RA (HR = 1.51; 95% CI, 0.82–2.77). We saw no elevations in risk in women living 50–200 m from the road. Conclusions: The observed association between exposure to traffic pollution and RA suggests that pollution from traffic in adulthood may be a newly identified environmental risk factor for RA
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