MODELAGEM DE COMBUSTÍVEIS FLORESTAIS NO PARQUE NACIONAL DO IGUAÇU, PR, BRASIL

The objectives of this research were to measure and model the surface forest fuel in the Iguaçu National Park. A total of 133 plots (1.0mx1.0m) were located in the Park area in order to collect the information needed to develop the investigation. Live and dead woody surface fuels were collected, separated and classified, generating the following groups: miscellanea (MIS); dead fuel, diameter ≤ 0.7 cm (L1M); dead fuel, diameter > 0.7cm (L2M); total woody dead fuel (LTM = L1M + L2M); total dead fuel (MLTM = MIS + LTM); live fuel, diameter ≤ 0.7cm (L1V); live fuel, diameter > 0.7cm (L2V); total woody live fuel (LTV = L1V + L2V); and total fuel load (CTC = MLTM+LTV). The independent variables measured were: litter depth (EMO); average DBH (DAP); basal area (G); and trees average height (H). The total fuel load measured through the sample plots varied from 1.75 to 21.72 ton.ha-1, with an average of 11.74 ton.ha-1. Models generated through the forward stepwise methodology could be considered a first approach to estimate the fuel load based on some easily obtained independent variables in the Iguaçu National Park. The best model to estimate total dead fuel load was (R2 = 0.57): MLTM = 951.639 + 20.179 (EMO3) – 800.441 (1/EMO) – 0,090 (G2 *EMO) + 14.982(G)and the best model to estimate the total fuel load was (R2 = 0.58): CTC = 1162.193 + 19.355 (EMO3) – 925.90 (1/EMO) – 0.086 (G2 *EMO) + 13.980 (G). It was not possible to generate a model to estimate live fuel load due to the lower determination coefficients obtained.O objetivo principal deste trabalho foi o desenvolvimento de equações matemáticas que estimem a carga de combustível superficial existente nas florestas do Parque Nacional do Iguaçu. O conhecimento da quantidade de combustível existente é importante para a previsão do comportamento do fogo caso ocorra um incêndio florestal na área. Os combustíveis coletados, vivos e mortos, em 133 parcelas de 1,0 x 1,0 m, foram classificados de acordo com suas naturezas e seus diâmetros, originando os seguintes grupos: miscelânea (MIS); combustíveis mortos com diâmetro £ 0,7 cm (L1M); combustíveis mortos com diâmetro > 0,7 cm (L2M); combustíveis lenhosos mortos (LTM = L1M + L2M; total de combustíveis mortos (MLTM = MIS + LTM); combustíveis vivos com diâmetro £ 0,7 cm (L1V); combustíveis vivos com diâmetro > 0,7 cm (L2V); total de combustíveis vivos (LTV = L1V + L2V); e carga total de combustíveis (CTC = MLTM + LTV). As variáveis independentes medidas e usadas na modelagem foram: espessura da manta orgânica (EMO); diâmetro médio à altura do peito (DAP); área basal (G); altura média das árvores (H). As cargas totais de combustíveis obtidas variaram de 1,75 a 21,72 T. ha–1, com uma média de 11,74 T. ha –1. O melhor modelo para estimar a carga de combustíveis mortos foi (R2 = 0,57): MLTM = 951,639 + 20,179 (EMO³) – 800,441 (1/EMO) – 0,090 (G²*EMO) + 14,982 (G). O melhor modelo para estimar a carga total de combustível foi (R2 = 0,58): CTC = 1162,193 + 19,355 (EMO³) – 925,90 (1/EMO) – 0,086 (G²*EMO) + 13,980 (G). Os valores obtidos na amostragem não permitiram o desenvolvimento de um modelo válido para estimar a carga de combustíveis vivos, devido aos baixos coeficientes de determinação

Molecular Evolution of Phosphoprotein Phosphatases in Drosophila

Phosphoprotein phosphatases (PPP), these ancient and important regulatory enzymes are present in all eukaryotic organisms. Based on the genome sequences of 12 Drosophila species we traced the evolution of the PPP catalytic subunits and noted a substantial expansion of the gene family. We concluded that the 18–22 PPP genes of Drosophilidae were generated from a core set of 8 indispensable phosphatases that are present in most of the insects. Retropositons followed by tandem gene duplications extended the phosphatase repertoire, and sporadic gene losses contributed to the species specific variations in the PPP complement. During the course of these studies we identified 5, up till now uncharacterized phosphatase retrogenes: PpY+, PpD5+, PpD6+, Pp4+, and Pp6+ which are found only in some ancient Drosophila. We demonstrated that all of these new PPP genes exhibit a distinct male specific expression. In addition to the changes in gene numbers, the intron-exon structure and the chromosomal localization of several PPP genes was also altered during evolution. The G−C content of the coding regions decreased when a gene moved into the heterochromatic region of chromosome Y. Thus the PPP enzymes exemplify the various types of dynamic rearrangements that accompany the molecular evolution of a gene family in Drosophilidae

Electrochemical investigation of the influence of thin SiO_<i>x</i> films deposited on gold on charge transfer characteristics

International audienceThe paper reports on the investigation of the electrochemical behavior of a thin gold film electrode coated with silicon dioxide (SiOx) layers of increasing thickness. Stable thin films of amorphous silica (SiOx) were deposited on glass slides coated with a 5 nm adhesion layer of titanium and 50 nm of gold, using plasma-enhanced chemical vapor deposition (PECVD) technique. Scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical behavior of the interfaces. In the case of SECM, the influence of the SiOx thicknesses on the electron transfer kinetics of three redox mediators was investigated. Normalized current–distance curves (approach curves) were fitted to the theoretical model in order to find the effective heterogeneous first order rate constant (keff) at the sample. EIS was in addition used to confirm the diffusion barrier character of the SiOx interlayer

Landscape-scale controls on the spatial distribution of caesium 137: a study based on an airborne geophysical survey across Northern Ireland

The spatial distribution of 137Cs across the landscape and the processes controlling its redistribution are of interest because (i) 137Cs has been widely used to quantify the movement of soil and sediments and (ii) substantial fallout of 137Cs after the Chernobyl accident has led to contamination of foodstuffs in some places. A high-resolution airborne geophysical radiometric survey of Northern Ireland has provided an opportunity to study the distribution and possible redistribution of 137Cs. The 137Cs activity (recorded at 1·2 million points) is distributed in a series of bands oriented approximately 160° and 115° clockwise from north. Geostatistical analysis of the data shows a strong, short-range structure (correlation ranges between 0·6 and 8 km) in 137Cs activity across the vast majority of the region; the spatial distribution shows association with a published, coarse-scale depositional pattern of 137Cs from Chernobyl. Two indices of land form derived from a digital elevation model, namely compound topographic index and the length–slope factor of the Revised Universal Soil Loss Equation, account for only 3% of the variance in 137Cs activity. In contrast, soil type and land cover in combination (including their interaction) account for 20% of the variance. In areas that received moderate fallout from Chernobyl, soil type alone accounts for a substantial proportion of the spatially correlated 137Cs activity. We attribute this to each soil type having a fairly uniform radiocaesium interception potential that differs from those of other soil types and that this potential controls the vertical migration of 137Cs. Over the granitic Mourne Mountains there is a strong spatial cross-correlation between 137Cs activity and airborne estimates of soil potassium, suggesting that the latter provides a measure of the soil's radiocaesium interception potential; this is probably dominated by the quantity of the mineral illit

Localized electropolymerization on oxidized boron-doped diamond electrodes modified with pyrrolyl units

International audienceThis paper describes the functionalization of oxidized boron-doped diamond (BDD) electrodes with N-(3-trimethoxysilylpropyl)pyrrole (TMPP) and the influence of this layer on the electrochemical transfer kinetics as well as on the possibility of forming strongly adhesive polypyrrole films on the BDD interface through electropolymerization. Furthermore, localized polymer formation was achieved on the TMPP-modified BDD interface using the direct mode of a scanning electrochemical microscope (SECM) as well as an electrochemical scanning near-field optical microscope (E-SNOM). Depending on the method used polypyrrole dots with diameters in the range of 1250 μm are electrogenerated

Chapter 56 - The Impact of Ethanol Plus Caffeine Exposure on Cognitive, Emotional, and Motivational Effects Related to Social Functioning

The impact of caffeine on ethanol consumption and abuse has become a topic of great interest due to the rise in popularity of energy drinks. Energy drinks have many different components, although the main active ingredient is caffeine. These drinks are frequently taken in combination with alcohol, with the belief that caffeine can offset some of the intoxicating effects of ethanol. However, scientific research has not universally supported the idea that caffeine can reduce the effects of ethanol in humans or in rodents, and the mechanisms mediating caffeine–ethanol interactions are not well understood. Caffeine acts as a nonselective adenosine A1 and A2A receptor antagonist, while ethanol has been demonstrated to increase the basal adenosinergic tone via multiple mechanisms. In this chapter, we discuss animal studies that have assessed the impact of ethanol plus caffeine combinations on social processes related to motivation, emotion, and cognition