Gap size measurement: the proposal of a new field method

In the tropical Atlantic Forest, 42 canopy gaps had their areas estimated using four different field methods of measurement: Runkle, Brokaw and Green [Runkle, J.R., 1981. Gap formation in some old-growth forests of the eastern United States. Ecology 62, 1041-1051; Brokaw, N.V.L., 1982. The definition of treefall gap and its effect on measures of forest dynamics. Biotropica 14, 158-160; Green, P.T., 1996. Canopy Gaps in rain forest on Christmas Island, Indian Ocean: size distribution and methods of measurement. J. Trop. Ecol. 12, 427-434] and a new method proposed in this work. It was found that within the same gap delimitation, average gap size varied from 56.0 up to 88.3 m(3) while total sum of gap area varied from 2351.3 to 3707.9 m(3) Differences among all methods and between pairs of method proved to be statistically significant. As a consequence, gap size-class distribution was also different between methods. When one method is held as a standard, deviation on average values of gap size ranged between 11.8 and 59.7% as deviations on single gap size can reach 172.8%. Implications on forest dynamics were expressed by the forest turnover rate that was 24% faster or 15% slower depending on the method adopted for gap measurement. Based on my results and on methods' evaluation, the use of a new method is proposed here for future research involving the measure of gap size in forest ecosystems. Finally, it is concluded that forest comparisons disregarding the influence of different methods of gap measurement should be reconsidered. (c) 2005 Elsevier B.V. All rights reserved.

Three-dimensional reconstruction of fracture surfaces: Area matching algorithms for automatic parallax measurements

This paper describes two solutions for systematic measurement of surface elevation that can be used for both profile and surface reconstructions for quantitative fractography case studies. The first one is developed under Khoros graphical interface environment. It consists of an adaption of the almost classical area matching algorithm, that is based on cross-correlation operations, to the well-known method of parallax measurements from stereo pairs. A normalization function was created to avoid false cross-correlation peaks, driving to the true window best matching solution at each region analyzed on both stereo projections. Some limitations to the use of scanning electron microscopy and the types of surface patterns are also discussed. The second algorithm is based on a spatial correlation function. This solution is implemented under the NIH Image macro programming, combining a good representation for low contrast regions and many improvements on overall user interface and performance. Its advantages and limitations are also presented.

Influence of angiotensin II receptor subtypes of the paraventricular nucleus on the physiological responses induced by angiotensin II injection into the medial septal area

Objective - We determined the effects of losartan and PD 123319 (antagonists of the AT1 and AT2 angiotensin receptors, respectively), and [Sar1, Ala8] ANG II (a relatively peptide antagonist of angiotensin receptors) injected into the paraventricular nucleus (PVN) on water and 3% NaCl intake, and the diuretic, natriuretic, and pressor effects induced by administration of angiotensin II (ANG II) into the medial septal area (MSA) of conscious rats. Methods - Holtzman rats were used. Animals were anesthetized with tribromoethanol (20 mg) per 100 grams of body weight, ip. A stainless steel guide cannula was implanted into the MSA and PVN. All drugs were injected in 0.5-μl volumes for 10-15 seconds. Seven days after brain surgery, water and 3% NaCl intake, urine and sodium excretion, and arterial blood pressure were measured. Results - Losartan (40 nmol) and [Sar1, Ala8] ANG II (40 nmol) completely eliminated whereas PD 123319 (40 nmol) partially blocked the increase in water and sodium intake and the increase in arterial blood pressure induced by ANG II (10 nmol) injected into the MSA. The PVN administration of PD 123319 and [Sar1, Ala8] ANG II blocked whereas losartan attenuated the diuresis and natriuresis induced by MSA administration of ANG II. Conclusion - MSA involvement with PVN on water and sodium homeostasis and arterial pressure modulation utilizing ANGII receptors is suggested.

Education and the labour market in Latin America: why measurement is important and what it tells us about policies, reforms and performance

Includes bibliography

Development of an instrumentation system embedded on FPGA for real time measurement of mechanical vibrations in rotating machinery

The real-time monitoring of events in an industrial plant is vital, to monitor the actual conditions of operation of the machinery responsible for the manufacturing process. A predictive maintenance program includes condition monitoring of the rotating machinery, to anticipate possible conditions of failure. To increase the operational reliability it is thus necessary an efficient tool to analyze and monitor the equipments, in real-time, and enabling the detection of e.g. incipient faults in bearings. To fulfill these requirements some innovations have become frequent, namely the inclusion of vibration sensors or stator current sensors. These innovations enable the development of new design methodologies that take into account the ease of future modifications, upgrades, and replacement of the monitored machine, as well as expansion of the monitoring system. This paper presents the development, implementation and testing of an instrument for vibration monitoring, as a possible solution to embed in industrial environment. The digital control system is based on an FPGA, and its configuration with an open hardware design tool is described. Special focus is given to the area of fault detection in rolling bearings. © 2012 IEEE.

Performance measurement and indicators for water supply management: review and international cases

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biomass burning fuel consumption rates: a field measurement database

Landscape fires show large variability in the amount of biomass or fuel consumed per unit area burned. Fuel consumption (FC) depends on the biomass available to burn and the fraction of the biomass that is actually combusted, and can be combined with estimates of area burned to assess emissions. While burned area can be detected from space and estimates are becoming more reliable due to improved algorithms and sensors, FC is usually modeled or taken selectively from the literature. We compiled the peerreviewed literature on FC for various biomes and fuel categories to understand FC and its variability better, and to provide a database that can be used to constrain biogeochemical models with fire modules. We compiled in total 77 studies covering 11 biomes including savanna (15 studies, average FC of 4.6 t DM (dry matter) ha 1 with a standard deviation of 2.2), tropical forest (n = 19, FC = 126 +/- 77), temperate forest (n = 12, FC = 58 +/- 72), boreal forest (n = 16, FC = 35 +/- 24), pasture (n = 4, FC = 28 +/- 9.3), shifting cultivation (n = 2, FC = 23, with a range of 4.0-43), crop residue (n = 4, FC = 6.5 +/- 9.0), chaparral (n = 3, FC = 27 +/- 19), tropical peatland (n = 4, FC = 314 +/- 196), boreal peatland (n = 2, FC = 42 [42-43]), and tundra (n = 1, FC = 40). Within biomes the regional variability in the number of measurements was sometimes large, with e. g. only three measurement locations in boreal Russia and 35 sites in North America. Substantial regional differences in FC were found within the defined biomes: for example, FC of temperate pine forests in the USA was 37% lower than Australian forests dominated by eucalypt trees. Besides showing the differences between biomes, FC estimates were also grouped into different fuel classes. Our results highlight the large variability in FC, not only between biomes but also within biomes and fuel classes. This implies that substantial uncertainties are associated with using biome-averaged values to represent FC for whole biomes. Comparing the compiled FC values with co-located Global Fire Emissions Database version 3 (GFED3) FC indicates that modeling studies that aim to represent variability in FC also within biomes, still require improvements as they have difficulty in representing the dynamics governing FC.

Analysis of simple hardware efficiency for temperature measurement in agriculture and environment

This work focuses basically on the design and analysis of simple and low cost hardware systems efficiency for temperature measurement in agricultural area. The main objective is to prove quantitatively, through statistical data analysis, to what extent a simple hardware designed with inexpensive components can be used safely in the indoor temperature measurement in farm buildings, such as greenhouses, warehouse or silos. To verify the of simple hardware efficiency, its data were compared with data from measurements with a high performance LabVIEW platform. This work proved that a simple hardware based on a microcontroller and the LM35 sensor can perform well. It presented a good accuracy but a relatively low precision that can be improved when performed some consecutive signal sampling and then used its average value. Although there are many papers that explain these components, this work has the distinction of presenting a data analysis in numerical form and using high performance systems to ensure critical data comparison.

Urban Air Pollutants are Significant Risk Factors for Asthma and Pneumonia in Children: The Influence of Location on the Measurement of Pollutants

Background: Air pollution is associated with a substantial burden on human health; however, the most important pollutants may vary with location. Proper monitoring is necessary to determine the effect of these pollutants on respiratory health. Objectives: This study was designed to evaluate the role of outdoor, indoor and personal exposure to combustion-related pollutants NO2 and O-3 on respiratory health of children in a non-affluent urban area of Sao Paulo, Brazil. Methods: Levels of NO2 and O-3 were continuously measured in outdoor and indoor air, as well as personal exposure, for 30 days using passive measurement monitors. Respiratory health was assessed with a Brazilian version of the ISAAC questionnaire. Results: Complete data were available from 64 children, aged 6-10 years. Respiratory morbidity was high, with 43 (67.2%) reporting having had wheezing at any time, 27 (42.2%) wheezing in the last month, 17 (26.6%) asthma at any time and 21(32.8%) pneumonia at any time. Correlations between levels of NO2 and O-3 measured in the three locations evaluated were poor. Levels of NO2 in indoor air and personal exposure to O-3 were independently associated with asthma (both cases P=.02), pneumonia (O-3, P=.02) and wheezing at any time (both cases P<.01). No associations were seen between outdoor NO2 and O-3 and respiratory health. Conclusions: Exposure to higher levels of NO2 and O-3 was associated with increased risk for asthma and pneumonia in children. Nonetheless, the place where the pollutants are measured influences the results. The measurements taken in indoor and personal exposure were the most accurate. (C) 2012 SEPAR. Published by Elsevier Espana, S.L. All rights reserved.

Delineation of vertebral area on the coronal plane using three-dimensional ultrasonography advanced volume contrast imaging (VCI) Omni view: intrarater reliability and agreement using standard mouse, high definition mouse, and pen-tablet

Objective: To assess the fetal lumbosacral spine by three-dimensional (3D) ultrasonography using volume contrast imaging (VCI) omni view method and compare reproducibility and agreement between three different measurement techniques: standard mouse, high definition mouse and pen-tablet. Methods: A comparative and prospective study with 40 pregnant women between 20 and 34+6 weeks was realized. 3D volume datasets of the fetal spine were acquired using a convex transabdominal transducer. Starting scan plane was the coronal section of fetal lumbosacral spine by VCI-C function. Omni view manual trace was selected and a parallel plane of fetal spine was drawn including interest region. Intraclass correlation coefficient (ICC) was used for reproducibility analysis. The relative difference between three used techniques was compared by chi-square test and Fischer test. Results: Pen-tablet showed better reliability (ICC = 0.987). In the relative proportion of differences, this was significantly higher for the pen-tablet (82.14%; p < 0.01). In paired comparison, the relative difference was significantly greater for the pen-tablet (p < 0.01). Conclusion: The pen-tablet showed to be the most reproductive and concordant method in the measurement of body vertebral area of fetal lumbosacral spine by 3D ultrasonography using the VCI.

Development and characterization of a distributed measurement system for the evaluation of voltage quality in electric power networks

The research activity carried out during the PhD course in Electrical Engineering belongs to the branch of electric and electronic measurements. The main subject of the present thesis is a distributed measurement system to be installed in Medium Voltage power networks, as well as the method developed to analyze data acquired by the measurement system itself and to monitor power quality. In chapter 2 the increasing interest towards power quality in electrical systems is illustrated, by reporting the international research activity inherent to the problem and the relevant standards and guidelines emitted. The aspect of the quality of voltage provided by utilities and influenced by customers in the various points of a network came out only in recent years, in particular as a consequence of the energy market liberalization. Usually, the concept of quality of the delivered energy has been associated mostly to its continuity. Hence the reliability was the main characteristic to be ensured for power systems. Nowadays, the number and duration of interruptions are the “quality indicators” commonly perceived by most customers; for this reason, a short section is dedicated also to network reliability and its regulation. In this contest it should be noted that although the measurement system developed during the research activity belongs to the field of power quality evaluation systems, the information registered in real time by its remote stations can be used to improve the system reliability too. Given the vast scenario of power quality degrading phenomena that usually can occur in distribution networks, the study has been focused on electromagnetic transients affecting line voltages. The outcome of such a study has been the design and realization of a distributed measurement system which continuously monitor the phase signals in different points of a network, detect the occurrence of transients superposed to the fundamental steady state component and register the time of occurrence of such events. The data set is finally used to locate the source of the transient disturbance propagating along the network lines. Most of the oscillatory transients affecting line voltages are due to faults occurring in any point of the distribution system and have to be seen before protection equipment intervention. An important conclusion is that the method can improve the monitored network reliability, since the knowledge of the location of a fault allows the energy manager to reduce as much as possible both the area of the network to be disconnected for protection purposes and the time spent by technical staff to recover the abnormal condition and/or the damage. The part of the thesis presenting the results of such a study and activity is structured as follows: chapter 3 deals with the propagation of electromagnetic transients in power systems by defining characteristics and causes of the phenomena and briefly reporting the theory and approaches used to study transients propagation. Then the state of the art concerning methods to detect and locate faults in distribution networks is presented. Finally the attention is paid on the particular technique adopted for the same purpose during the thesis, and the methods developed on the basis of such approach. Chapter 4 reports the configuration of the distribution networks on which the fault location method has been applied by means of simulations as well as the results obtained case by case. In this way the performance featured by the location procedure firstly in ideal then in realistic operating conditions are tested. In chapter 5 the measurement system designed to implement the transients detection and fault location method is presented. The hardware belonging to the measurement chain of every acquisition channel in remote stations is described. Then, the global measurement system is characterized by considering the non ideal aspects of each device that can concur to the final combined uncertainty on the estimated position of the fault in the network under test. Finally, such parameter is computed according to the Guide to the Expression of Uncertainty in Measurements, by means of a numeric procedure. In the last chapter a device is described that has been designed and realized during the PhD activity aiming at substituting the commercial capacitive voltage divider belonging to the conditioning block of the measurement chain. Such a study has been carried out aiming at providing an alternative to the used transducer that could feature equivalent performance and lower cost. In this way, the economical impact of the investment associated to the whole measurement system would be significantly reduced, making the method application much more feasible.

Portal hypertension: a comparison between portal-venous pressure measurement and ARFI measurement of liver and spleen stiffness

PURPOSE. Portal pressure is measured invasively as Hepatic Venous Pressure Gradient (HVPG) in the angiography room. Liver stiffness measured by Fibroscan was shown to correlate with HVPG values below 12 mmHg. This is not surprising, since in cirrhosis the increase of portal pressure is not directly linked with liver fibrosis and consequently to liver stiffness. We hypothesized that, given the spleen’s privileged location upstream to the whole portal system, splenic stiffness could provide relevant information about portal pressure. Aim of the study was to assess the relationship between liver and spleen stiffness measured by Virtual Touch™ (ARFI) and HVPG in cirrhotic patients. METHODS. 40 consecutive patients (30 males, mean age 62y, mean BMI=26, mean Child-Pugh A6, mean platelet count=92.000/mmc, 19 HCV+, 7 with ascites) underwent to ARFI stiffness measurement (10 valid measurements in right liver lobe both surface and centre, left lobe and 20 in the spleen) and HPVG, blindly to each other. Median ARFI values of 10 samplings on every liver area and of 20 samplings on spleen were calculated. RESULTS. Stiffness could be easily measured in all patients with ARFI, resulting a mean of 2,61±0,76, 2,5±0,62 and 2,55±0,66 m/sec in the liver areas and 3.3±0,5 m/s in the spleen. Median HPVG was 14 mmHg (range 5-27); 28 patients showed values ≥10 mmHg. A positive significant correlation was found between spleen stiffness and HPVG values (r=0.744, p<0.001). No significant correlation was found between all liver stiffness and HVPG (p>0,05). AUROC was calculated to test spleen stiffness ability in discriminating patients with HVPG ≥10. AUROC = 0.911 was obtained, with sensitivity of 69% and specificity of 91% at a cut-off of 3.26 m/s. CONCLUSION. Spleen stiffness measurement with ARFI correlates with HVPG in patients with cirrhosis, with a potential of identifying patients with clinically significant portal hypertension.

Measurement of volatile organic compounds and total OH reactivity in the atmosphere

Volatile organic compounds play a critical role in ozone formation and drive the chemistry of the atmosphere, together with OH radicals. The simplest volatile organic compound methane is a climatologically important greenhouse gas, and plays a key role in regulating water vapour in the stratosphere and hydroxyl radicals in the troposphere. The OH radical is the most important atmospheric oxidant and knowledge of the atmospheric OH sink, together with the OH source and ambient OH concentrations is essential for understanding the oxidative capacity of the atmosphere. Oceanic emission and / or uptake of methanol, acetone, acetaldehyde, isoprene and dimethyl sulphide (DMS) was characterized as a function of photosynthetically active radiation (PAR) and a suite of biological parameters, in a mesocosm experiment conducted in the Norwegian fjord. High frequency (ca. 1 minute-1) methane measurements were performed using a gas chromatograph - flame ionization detector (GC-FID) in the boreal forests of Finland and the tropical forests of Suriname. A new on-line method (Comparative Reactivity Method - CRM) was developed to directly measure the total OH reactivity (sink) of ambient air. It was observed that under conditions of high biological activity and a PAR of ~ 450 μmol photons m-2 s-1, the ocean acted as a net source of acetone. However, if either of these criteria was not fulfilled then the ocean acted as a net sink of acetone. This new insight into the biogeochemical cycling of acetone at the ocean-air interface has helped to resolve discrepancies from earlier works such as Jacob et al. (2002) who reported the ocean to be a net acetone source (27 Tg yr-1) and Marandino et al. (2005) who reported the ocean to be a net sink of acetone (- 48 Tg yr-1). The ocean acted as net source of isoprene, DMS and acetaldehyde but net sink of methanol. Based on these findings, it is recommended that compound specific PAR and biological dependency be used for estimating the influence of the global ocean on atmospheric VOC budgets. Methane was observed to accumulate within the nocturnal boundary layer, clearly indicating emissions from the forest ecosystems. There was a remarkable similarity in the time series of the boreal and tropical forest ecosystem. The average of the median mixing ratios during a typical diel cycle were 1.83 μmol mol-1 and 1.74 μmol mol-1 for the boreal forest ecosystem and tropical forest ecosystem respectively. A flux value of (3.62 ± 0.87) x 1011 molecules cm-2 s-1 (or 45.5 ± 11 Tg CH4 yr-1 for global boreal forest area) was derived, which highlights the importance of the boreal forest ecosystem for the global budget of methane (~ 600 Tg yr-1). The newly developed CRM technique has a dynamic range of ~ 4 s-1 to 300 s-1 and accuracy of ± 25 %. The system has been tested and calibrated with several single and mixed hydrocarbon standards showing excellent linearity and accountability with the reactivity of the standards. Field tests at an urban and forest site illustrate the promise of the new method. The results from this study have improved current understanding about VOC emissions and uptake from ocean and forest ecosystems. Moreover, a new technique for directly measuring the total OH reactivity of ambient air has been developed and validated, which will be a valuable addition to the existing suite of atmospheric measurement techniques.

Continuous geochemical monitoring by mass-spectometer in the Campi Flegrei geothermal area. An application at Pisciarelli-Solfatara (diffuse and fumarolic gases) and at the mud gases during drilling of the CFDDP pilot hole

During this work has been developed an innovative methodology for continuous and in situ gas monitoring (24/24 h) of fumarolic and soil diffusive emissions applied to the geothermal and volcanic area of Pisciarelli near Agnano inside the Campi Flegrei caldera (CFc). In literature there are only scattered and in discrete data of the geochemical gas composition of fumarole at Campi Flegrei; it is only since the early ’80 that exist a systematic record of fumaroles with discrete sampling at Solfatara (Bocca Grande and Bocca Nuova fumaroles) and since 1999, even at the degassing areas of Pisciarelli. This type of sampling has resulted in a time series of geochemical analysis with discontinuous periods of time set (in average 2-3 measurements per month) completely inadequate for the purposes of Civil Defence in such high volcanic risk and densely populated areas. For this purpose, and to remedy this lack of data, during this study was introduced a new methodology of continuous and in situ sampling able to continuously detect data related and from its soil diffusive degassing. Due to its high sampling density (about one measurement per minute therefore producing 1440 data daily) and numerous species detected (CO2, Ar, 36Ar, CH4, He, H2S, N2, O2) allowing a good statistic record and the reconstruction of the gas composition evolution of the investigated area. This methodology is based on continuous sampling of fumaroles gases and soil degassing using an extraction line, which after undergoing a series of condensation processes of the water vapour content - better described hereinafter - is analyzed through using a quadrupole mass spectrometer

Accuracy of liver stiffness measurement using fibroscan ® to predict the response to antiviral therapy in patients with chronic hepatitis c viral infection

Introduction: Antiviral therapy can prevent disease progression in patients with chronic hepatitis C . Transient Elastografy (TE; Fibroscan) is an accurate surrogate marker to liver fibrosis, by measuring liver stiffness (LS). LS decrease has been associated with sustained virologic response (SVR). Aim: to assess the changes of LS measurments in CHC patients during and one year after Interferon (IFN)-based antiviral therapy (IFN/ribavirin) or (telaprevir+IFN/ribavirin). Methods: consecutive 69 CHC patients (53.6% females, mean age 57.9 ± 11.4) who underwent antiviral therapy for at least 20 weeks were enrolled. LS was measured using FibroScan at baseline, after three months, at the end of treatment and one year after treatment discontinuation. Fibrosis was graded using METAVIR score. Results: twenty patients treated with triple therapy and 49 with IFN/ribavirin. Fifty patients had SVR and 19 were non-responders. SVR patients: F0-F1, F2 and F3 patients (39.1%, 7.2% and 17.4%; respectively) showed no significant LS decrease (P= 0.186, 0.068 and 0.075; respectively). Conversely, in F4 patients (36.2%) LS was significantly decreased (P=0.015) after one year of treatment completion. In all patients with no SVR, no significant decrease in LS was observed. Interestingly, all Patients with F4 fibrosis (even non-responders) showed an initial significant decrease in LS (P=0.024) at 3 months after the start of treatment. However, this decrease was not predictive of SVR; area under the ROC curve 0.369 (CI %: 0.145-0.592) P= 0.265. Conclusion: Our study showed that initial decrease in LSM, especially in patients with higher baseline fibrosis score is unlikely to predict an SVR. In addition no significant association was found between clinical or virological parameters and fibrosis improvement. Further studies are needed to delineate the most appropriate clinical scenarios for the LSM by Fibroscan in chronic hepatitis C and its role in monitoring the response to antiviral treatment.