98 research outputs found

    Estudo da humidade e actividade de água de pranchas de cortiça durante o processo de fabrico de rolhas de cortiça - resultados preliminares

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    The main goal of this work was to make evidence of the applicability in the cork stopper industry of a control method along the cork slabs maturing stage after boiling, aiming to ensure the adequate conditions for Chrysonilia sitophila colonisation of cork slabs during that period, avoiding the development of other fungi. Cork humidity and water activity (wa) were used as indicators. Comparing the drying rate of the outer and the inner parts of the bark it could be observed, under the assay conditions, that to attain 0.9 wa, (the critical point for C. sitophila development), 39.8h were necessary in the case of outer bark while inner bark only need 20.4h. As the visible part of the cork slabs corresponds more to its outer part, the time of 40h can be taken as a good visible indicator to limit the cork slabs maturing period after boiling. Moreover it could be observed that under that period of time the evident prevailing fungus on the cork slabs was C. sitophila so probably assuring low probabilities of ‘cork taint’ occurrence, under the conditions propose on this study

    Global analysis of radiative forcing from fire-induced shortwave albedo change

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    Land surface albedo, a key parameter to derive Earth’s surface energy balance, is used in the parameterization of numerical weather prediction, climate monitoring and climate change impact assessments. Changes in albedo due to fire have not been fully investigated on a continental and global scale. The main goal of this study, therefore, is to quantify the changes in instantaneous shortwave albedo produced by biomass burning activities and their associated radiative forcing. The study relies on the MODerate-resolution Imaging Spectroradiometer (MODIS) MCD64A1 burned-area product to create an annual composite of areas affected by fire and the MCD43C2 bidirectional reflectance distribution function (BRDF) albedo snow-free product to compute a bihemispherical reflectance time series. The approximate day of burning is used to calculate the instantaneous change in shortwave albedo. Using the corresponding National Centers for Environmental Prediction (NCEP) monthly mean downward solar radiation flux at the surface, the global radiative forcing associated with fire was computed. The analysis reveals a mean decrease in shortwave albedo of 0.014 (1 D 0:017), causing a mean positive radiative forcing of 3.99Wm2 (1 D 4:89) over the 2002–20012 time period in areas affected by fire. The greatest drop in mean shortwave albedo change occurs in 2002, which corresponds to the highest total area burned (378 Mha) observed in the same year and produces the highest mean radiative forcing (4.5Wm2). Africa is the main contributor in terms of burned area, but forests globally give the highest radiative forcing per unit area and thus give detectable changes in shortwave albedo. The global mean radiative forcing for the whole period studied ( 0.0275Wm2) shows that the contribution of fires to the Earth system is not insignificantinfo:eu-repo/semantics/publishedVersio

    The Alchemist

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    This investigation uses a recent methodology, essentially based on our evolutionary algorithm (EA) to get new insights about the energetics and structure of the first solvation shells of lithium ion in polar solvents that form important hydrogen bonds. We employed the EA to search for the low-energy structures of the Li+(H2O)n and Li+(CH3OH)n clusters (with n ⩽ 20) as modeled by commonly used rigid nonpolarizable force-field potentials. Particular emphasis is given to the characterization of the putative global minima; for Li+(H2O)17, the EA discovered a new global minimum with five water molecules directly coordinating the ion. Smaller-size clusters were, then, re-optimized by employing electronicstructure methods, namely, DFT (with the B3LYP functional and both the 6-31+G∗ and 6-311+G∗∗ basis sets) and MP2 (with the aug-cc-pVDZ basis set). In the case of Li+(H2O)n, the ab initio global minimum structures are similar to those obtained with the EA up to n = 10. However, for n = 17, the structure of the global minimum discovered by the EA is different from the lowest-energy cluster obtained after re-optimization at the MP2/aug-cc-pVDZ level of theory. Such energy reorder may be attributed to the water–water interaction. As for the Li+(CH3OH)n clusters, the re-optimization process leads more often to a reorder in the energy of the minimum structures. Thus, forfluxional clusters like the Li+(CH3OH)n ones that show a huge number of stationary configurations within a small energy window, it is mandatory to carefully choose various structures, besides the global minimum, to be re-optimized at the ab initio or DFT levels. Due to the difficulty on choosing adequate departing structures by the usually employed chemical intuition, we noticed that some low-energy minima (including the global one) of even small Li+(CH3OH)n clusters were missed in literature. We showcase this problem in the Li+(CH3OH)6 cluster, whose vibrational frequencies in the C–O stretching region and corresponding infrared intensities were calculated at the DFT level of theory and compared with previously reported results

    Fire frequency analysis in Portugal (1975-2005), using Landsat-based burnt area maps

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    Fire frequency in 21 forest planning regions of Portugal during the period 1975–2005 was estimated from historical burnt area maps generated with semi-automatic classification of Landsat Thematic Mapper (TM) satellite imagery. Fire return interval distributions were modelled with the Weibull function and the estimated parameters were used to calculate regional mean, median and modal fire return intervals, as well as regional hazard functions. Arrangement of the available data into three different time series allowed for assessment of the effects of minimum mapping unit, time series length and use of censored data on the Weibull function parameter estimates. Varying the minimum mapping unit between 5 and 35 ha had a negligible effect on parameter estimates, whereas changing the time series length from 22 to 31 years substantially affected the estimates. However, the strongest effect was caused by censored data. Its exclusion led to substantial overestimation of fire frequency and of burning probability dependence on fuel age. We estimated a countrywide mean fire interval of 36 years and an annual burnt area of 1.2%. Regional variations in fire frequency descriptors were interpreted in terms of land cover and land use practices that affect the contemporary fire regime in Portugal

    Identifying geographical patterns of wildfire orientation: a watershed-based analysis

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    We searched for geographical patterns in the orientation of wildfires, using watersheds as spatial support for the analysis. An 1975–2005 annual fire atlas of mainland Portugal was used to compute the orientation of fire perimeters and watersheds, using principal component analysis. Circular statistics were employed to test for the existence of a preferred, as opposed to random, mean fire orientation in each watershed, and to search for evidence of orographic channelling of fire by comparing fire orientation and watershed orientation. We also tested for differences in fire orientation patterns under conditions of mild versus severe fire weather. Our findings show that in the 31 year period of the study, 84% of the overall area burned is accounted for by watersheds where fires display preferential orientation. Twelve of 102 watersheds display evidence of alignment between fire and watershed orientation and we found no distinction in fire orientation as response to fire weather. The spatial arrangement of watersheds where fires present similar orientation suggests wind as a major driver of the broader patterns found in this study. Results from this analysis ought to be relevant for supporting the delineation of landscape- scale fuelbreaks

    HESFIRE: a global fire model to explore the role of anthropogenic and weather drivers

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    Vegetation fires are a major driver of ecosystem dynamics and greenhouse gas emissions. Anticipating potential changes in fire activity and their impacts relies first on a realistic model of fire activity (e.g., fire incidence and interannual variability) and second on a model accounting for fire impacts (e.g., mortality and emissions). In this paper, we focus on our understanding of fire activity and describe a new fire model, HESFIRE (Human–Earth System FIRE), which integrates the influence of weather, vegetation characteristics, and human activities on fires in a stand-alone framework. It was developed with a particular emphasis on allowing fires to spread over consecutive days given their major contribution to burned areas in many ecosystems. A subset of the model parameters was calibrated through an optimization procedure using observation data to enhance our knowledge of regional drivers of fire activity and improve the performance of the model on a global scale. Modeled fire activity showed reasonable agreement with observations of burned area, fire seasonality, and interannual variability in many regions, including for spatial and temporal domains not included in the optimization procedure. Significant discrepancies are investigated, most notably regarding fires in boreal regions and in xeric ecosystems and also fire size distribution. The sensitivity of fire activity to model parameters is analyzed to explore the dominance of specific drivers across regions and ecosystems. The characteristics of HESFIRE and the outcome of its evaluation provide insights into the influence of anthropogenic activities and weather, and their interactions, on fire activityinfo:eu-repo/semantics/publishedVersio

    The North Atlantic oscillation and European vegetation dynamics

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    The relationship between vegetation greenness and the North Atlantic Oscillation (NAO) is assessed over Europe. The study covers the 21-year period from 1982 to 2002 and is based on monthly composites of the Normalised Difference Vegetation Index (NDVI) and Brightness Temperature from the Global Inventory Monitoring and Modelling System (GIMMS) as well as on monthly precipitation from the Global Precipitation Climatology Centre (GPCC). A systematic analysis is first performed of point correlation fields over the 21-year period between the winter NAO index and spring and summer NDVI, followed by an assessment of the vegetation response to precipitation and temperature conditions in winter, over two contrasting regions, namely the Iberian Peninsula and Northeastern Europe. Finally, the impact of NAO on vegetation dynamics over the two regions is evaluated by studying the corresponding annual cycles of NDVI and comparing their behaviour for years associated with opposite NAO phases. Over the Iberian Peninsula there is strong evidence that positive (negative) values of winter NAO induce low (high) vegetation activity in the following spring and summer seasons. This feature is mainly associated with the impact of NAO on winter precipitation, together with the strong dependence of spring and summer NDVI on water availability during the previous winter. Northeastern Europe shows a different behaviour, with positive (negative) values of winter NAO inducing high (low) values of NDVI in spring, but low (high) values of NDVI in summer. This behaviour mainly results from the strong impact of NAO on winter temperature, associated with the critical dependence of vegetation growth on the combined effect of warm conditions and water availability during the winter seaso

    Gabapentin Bioequivalence Study: Quantification By Liquid Chromatography Coupled To Mass Spectrometry

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    The study was performed to compare the bioavailability of two gabapentin 400 mg capsule formulation (Gabapentin from Arrow Farmacêutica S/A as test formulation and Neurontin ® from Pfizer, Brazil, as reference formulation) in 26 volunteers of both sexes. The study was conducted open with randomized two period crossover design and a one week wash out period. Plasma samples were obtained over a 48 hour interval. The gabapentin was analyzed by LC/MS/MS, in the presence of pracetamole as internal standard. With plasma concentration vs. time curves, data obtained from this metabolite, the following pharmacokinetics parameters were obtained: AUC 0-t, AUC 0-inf and C max. Geometric mean of gabapentin/Neurontin ® 400 mg individual percent ratio was 100.58% AUC 0-t, 101.35% for AUC 0-inf and 97.76% for C max. The 90% confidence intervals were 92.00 - 109.95%, 93.00 - 110.44%, 88.41 - 108.10%, respectively. Since the 90% confidence intervals for C max, AUC 0-t and AUC 0 -inf were within the 80 - 125% interval proposed by Food and Drug Administration, it was concluded that gabapentin 400 mg capsule was bioequivalent to Neurontin ® 400 mg capsule according to both the rate and extent of absorption. © 2011 Junior EA, et al.38187190Wattananat, T., Akarawut, W., Validated LC-MS-MS Method for the Determination of Gabapentin in Human Plasma: Application to a Bioequivalence Study (2009) J Chromatogr Sci, 47, pp. 868-871Stewart, B.H., Kagler, A.R., Thompson, P.R., Bockbrader, H.N., A saturable transport mechanism in the intestinal absorption of gabapentin is the underlying cause of the lack of proportionality between increasing dose and drug levels in plasma (1993) Pharma Res, 10, pp. 276-281McLean, M.J., Gabapentin in the management of convulsive disorders (1999) Epilepsia, 40, pp. 39-50Goa, K.L., Sorkin, E.M., Gabapentin: A review of its pharmacological properties and clinical potential in epilepsy (1993) Drugs, 46, pp. 409-427Zhu, Z., Neirinck, L., High-performance liquid chromatographic method for the determination of gabapentin in human plasma (2002) J Chromatogr B Analyt Technol Biomed Life Sci, 779, pp. 307-312Sagirli, O., Cetin, S.M., Determination of gabapentin in human plasma and urine by high-performance liquid chromatography with UV-vis detection (2006) J Pharm Biomed Anal, 42, pp. 618-624Jalalizadeh, H., Souri, E., Tehrani, M.B., Jahangiri, A., Validated HPLC method for the determination of gabapentin in human plasma using precolumn derivatization with 1-fluoro-2,4-dinitrobenzene and its application to a pharmacokinetic study (2007) J Chromatogr B Analyt Technol Biomed Life Sci, 854, pp. 43-47Forrest, G., Sills, G.J., Leach, J.P., Brodie, M.J., Determination of gabapentin in plasma by high-performance liquid chromatography (1996) J Chromatogr B Analyt Technol Biomed Life Sci, 681, pp. 421-425Tang, P.H., Miles, M.V., Glauser, T.A., Degrauw, T., Automated microanalysis of gabapentin in human serum by high-performance liquid chromatography with fluorometric detection (1999) J Chromatogr B Analyt Technol Biomed Life Sci, 727, pp. 125-129Hassan, E.M., Belal, F., Al-Deeb, O.A., Khalil, N.Y., Spectrofluorimetric determination of vigabatrin and gabapentin in dosage forms and spiked plasma samples through derivatization with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (2001) J. AOAC Int., 84, pp. 1017-1024Gauthier, D., Gupta, R., Determination of gabapentin in plasma by liquid chromatography with fluorescence detection after solid-phase extraction with a C18 column (2002) Clin Chem, 48, pp. 2259-2261Chung, T.C., Tai, C.T., Wu, H.L., Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma (2006) J Chromatogr A, 119, pp. 294-298Bahrami, G., Kiani, A., Sensitive high-performance liquid chromatographic quantitation of gabapentin in human serum using liquid-liquid extraction and pre-column derivatization with 9-fluorenylmethyl chloroformate (2006) J Chromatogr B Analyt Technol Biomed Life Sci, 835, pp. 123-126Krivanek, P., Koppatz, K., Turnheim, K., Simultaneous isocratic HPLC determination of vigabatrin and gabapentin in human plasma by dansyl derivatization (2003) Ther Drug Monit, 25, pp. 374-377Chang, S.Y., Wang, F.Y., Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma (2004) J Chromatogr B Analyt Technol Biomed Life Sci, 799, pp. 265-270Wolf, C.E., Saady, J.J., Poklis, A., Determination of gabapentin in serum using solid phase extraction and gas-liquid chromatography (1996) J Anal Toxicol, 20, pp. 498-501Kushnir, M.M., Cossett, J., Brown, P.I., Urry, F.M., Analysis of gabapentin in serum and plasma by solid-phase extraction and gas chromatography-mass spectrometry for therapeutic drug monitoring (1999) J Anal Toxicol, 23, pp. 1-6Borrey, D.C., Godderis, K.O., Engelrelst, V.I., Bernard, D.R., Langlois, M.R., Quantitative determination of vigabatrin and gabapentin in human serum by gas chromatography-mass spectrometry (2005) Clin Chim Acta, 354, pp. 147-151Gambelunghe, C., Mariucci, G., Tantucci, M., Ambrosini, M.V., Gas chromatography-tandemmass spectrometry analysis of gabapentin in serum (2005) Biomed Chromatogr, 19, pp. 63-67Matar, K.M., Abdel-Hamid, M.E., Rapid tandem mass spectrometric method for determination of gabapentin in human plasma (2005) Chromatographia, 61, pp. 499-504Ramakrishna, N.V.S., Vishwottam, K.N., Koteshwara, M., Maroj, S., Santosh, M., Rapid quantification of gabapentin in human plasma by liquid chromatography/tandemmass spectrometry (2006) J Pharm Biomed Anal, 40, pp. 360-368Ifa, D.R., Falci, M., Moraes, M.E., Bezerra, F.A., Moraes, M.O., Gabapentin quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry. 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    Global fire activity patterns (1996-2006) and climatic influence: an analysis using World Fire Atlas

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    Vegetation fires have been acknowledged as an environmental process of global scale, which affects the chemical composition of the troposphere, and has profound ecological and climatic impacts. However, considerable uncertainty remains, especially concerning intra and inter-annual variability of fire incidence. The main goals of our globalscale study were to characterise spatial-temporal patterns of fire activity, to identify broad geographical areas with similar vegetation fire dynamics, and to analyse the relationship between fire activity and the El Ni˜no-Southern Oscillation. This study relies on 10 years (mid 1996–mid 2006) of screened European Space Agency World Fire Atlas (WFA) data, obtained from Along Track Scanning Radiometer (ATSR) and Advanced ATSR (AATSR) imagery. Empirical Orthogonal Function analysis was used to reduce the dimensionality of the dataset. Regions of homogeneous fire dynamics were identified with cluster analysis, and interpreted based on their eco-climatic characteristics. The impact of 1997–1998 El Ni˜no is clearly dominant over the study period, causing increased fire activity in a variety of regions and ecosystems, with variable timing. Overall, this study provides the first global decadal assessment of spatialtemporal fire variability and confirms the usefulness of the screened WFA for global fire ecoclimatology researc

    Localization System for Optimization of Picking in a Manual Warehouse

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    Inbound logistics assumes increasing importance in retail operations, because there are usually hidden inefficiencies that contribute to higher labour costs and more time spent in the usual procedures in warehouses. The work developed was carried out in a manual warehouse of a retail company, with the main goal being the optimization of picking tasks and the improvement of the warehouse operations, as well as stock management. The solution is based on the development and implementation of a localization system, to reduce one of the most time-consuming components of picking, the search time for products in the warehouse. This application led to a reduction of this unproductive time by 93% to 100%, meaning the complete elimination of this component, which led to an optimization of the picking activity, by increasing the warehouse preparation capacity by 63%. Apart from the software upgrade, the operators now use Personal Digital Assistants to perform and validate the picking of items, increasing the accuracy of picking and the traceability of stock.info:eu-repo/semantics/publishedVersio
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