Alumina and Silica based Epoxy Nano-composites for Electrical Insulation

Plain epoxy resins or resin impregnated cellulose have found application as electrical insulation in power equipment. In the past, their performance was improved by the use of inorganic oxide fillers of microscopic dimensions. In the recent past nano-particle doped epoxy insulation came into use with a view to further enhance the dielectric properties. This paper reports dielectric investigations into epoxy nano-composites based on a class of metal oxides, Al2O3 and SiO2. In particular, consideration has been given to the partial discharge performance and electrical breakdown under different voltage profiles as a function of the volumetric composition of the nano-particles in epoxy resin.

SWEETENING OF BIOGAS IN SPRAY TOWERS FOR POWER GENERATION

This paper presents the experience of the new design of using impinging jet spray columns for scrubbing hydrogen sulfide from biogas that has been developed by Indian Institute of Science and patented. The process uses a chelated polyvalent metal ion which oxidizes the hydrogen sulfide to sulfur as a precipitate. The sulfur generated is filtered and the scrubbing liquid recycled after oxidation. The process involves in bringing contact the sour gas with chelated liquid in the spray columns where H2S reacts with chelated Fe3+ and precipitates as sulfur, whereas Fe3+ gets reduced to Fe2+. Fe2+ is regenerated to Fe3+ by reaction of oxygen in air in a separate packed column. The regenerated liquid is recirculated. Sulfur is filtered and separated as a byproduct. The paper presents the experience in using the spray towers for hydrogen sulfide removal and further use of the clean gas for generating power using gas engines. The maximum allowable limit of H2S for the gas engine is 200 ppm (v/v) in order to prevent any corrosion of engine parts and fouling of the lubricating oil. With the current ISET process, the hydrogen sulfide from the biogas is cleaned to less than 100 ppm (v/v) and the sweet gas is used for power generation. The system is designed for 550 NM3/hr of biogas and inlet H2S concentration of 2.5 %. The inlet concentration of the H2S is about 1 - 1.5 % and average measured outlet concentration is about 30 ppm, with an average gas flow of about 300 - 350 NM3/hr, which is the current gas production rate. The sweet gas is used for power generation in a 1.2 MWe V 12 engine. The average power generation is about 650 - 750 kWe, which is the captive load of the industry. The plant is a CHP (combined heat power) unit with heat from the cylinder cooling and flue being recovered for hot water and steam generation respectively. The specific fuel consumption is 2.29 kWh/m(3) of gas. The system has been in operation for more than 13,000 hours in last one year in the industry. About 8.4 million units of electricity has been generated scrubbing about 2.1 million m3 of gas. Performance of the scrubber and the engine is discussed at daily performance level and also the overall performance with an environment sustenance by precipitating over 27 tons of sulfur.

DECT evaluation of noncalc fied coronary artery plaque

Purpose: Composition of the coronary artery plaque is known to have critical role in heart attack. While calcified plaque can easily be diagnosed by conventional CT, it fails to distinguish between fibrous and lipid rich plaques. In the present paper, the authors discuss the experimental techniques and obtain a numerical algorithm by which the electron density (rho(e)) and the effective atomic number (Z(eff)) can be obtained from the dual energy computed tomography (DECT) data. The idea is to use this inversion method to characterize and distinguish between the lipid and fibrous coronary artery plaques. Methods: For the purpose of calibration of the CT machine, the authors prepare aqueous samples whose calculated values of (rho(e), Z(eff)) lie in the range of (2.65 x 10(23) <= rho(e) <= 3.64 x 10(23)/cm(3)) and (6.80 <= Z(eff) <= 8.90). The authors fill the phantom with these known samples and experimentally determine HU(V-1) and HU(V-2), with V-1,V-2 = 100 and 140 kVp, for the same pixels and thus determine the coefficients of inversion that allow us to determine (rho(e), Z(eff)) from the DECT data. The HU(100) and HU(140) for the coronary artery plaque are obtained by filling the channel of the coronary artery with a viscous solution of methyl cellulose in water, containing 2% contrast. These (rho(e), Z(eff)) values of the coronary artery plaque are used for their characterization on the basis of theoretical models of atomic compositions of the plaque materials. These results are compared with histopathological report. Results: The authors find that the calibration gives Pc with an accuracy of 3.5% while Z(eff) is found within 1% of the actual value, the confidence being 95%. The HU(100) and HU(140) are found to be considerably different for the same plaque at the same position and there is a linear trend between these two HU values. It is noted that pure lipid type plaques are practically nonexistent, and microcalcification, as observed in histopathology, has to be taken into account to explain the nature of the observed (rho(e), Z(eff)) data. This also enables us to judge the composition of the plaque in terms of basic model which considers the plaque to be composed of fibres, lipids, and microcalcification. Conclusions: This simple and reliable method has the potential as an effective modality to investigate the composition of noncalcified coronary artery plaques and thus help in their characterization. In this inversion method, (rho(e), Z(eff)) of the scanned sample can be found by eliminating the effects of the CT machine and also by ensuring that the determination of the two unknowns (rho(e), Z(eff)) does not interfere with each other and the nature of the plaque can be identified in terms of a three component model. (C) 2015 American Association of Physicists in Medicine.

Infiltration of Matrix-Non-producers Weakens the Salmonella Biofilm and Impairs Its Antimicrobial Tolerance and Pathogenicity

Bacterial biofilms display a collective lifestyle, wherein the cells secrete extracellular polymeric substances (EPS) that helps in adhesion, aggregation, stability, and to protect the bacteria from antimicrobials. We asked whether the BPS could act as a public good for the biofilm and observed that infiltration of cells that do not produce matrix components weakened the biofilm of Salmonella enterica serovar Typhimurium. PS production was costly for the producing cells, as indicated by a significant reduction in the fitness of wild type (WT) cells during competitive planktonic growth relative to the non-producers. Infiltration frequency of non-producers in the biofilm showed a concomitant decrease in overall productivity. It was apparent in the confocal images that the non producing cells benefit from the BPS produced by the Wild Type (WT) to stay in the biofilm. The biofilm containing non-producing cells were more significantly susceptible to sodium hypochlorite and ciprofloxacin treatment than the WT biofilm. Biofilm infiltrated with non-producers delayed the pathogenesis, as tested in a murine model. The cell types were spatially assorted, with non producers being edged out in the biofilm. However, cellulose was found to act as a barrier to keep the non-producers away from the WT microcolony. Our results show that the infiltration of non-cooperating cell types can substantially weaken the biofilm making it vulnerable to antibacterials and delay their pathogenesis. Cellulose, a component of BPS, was shown to play a pivotal role of acting as the main public good, and to edge-out the non-producers away from the cooperating microcolony.

Covalent interlocking of glucose oxidase and peroxidase in the voids of paper: enzyme-polymer ``spider webs''

A modular, general method for trapping enzymes within the voids of paper, without chemical activation of cellulose, is reported. Glucose oxidase and peroxidase were crosslinked with poly(acrylic acid) via carbodiimide chemistry, producing 3-dimensional networks interlocked in cellulose fibers. Interlocking prevented enzyme activity loss and enhanced the washability and stability.

Panama City Fisheries Resources Office: FY 2007 Annual Report

HIGHLIGHTS FOR FY 2007 1. Completed a three-year Gulf sturgeon population study on the Escambia River, Florida. The population was estimated at 451 fish. 2. Implemented the Gulf Striped Bass Restoration Plan by coordinating the 24th Annual Morone Workshop, leading the technical committee, transporting broodfish, coordinating stocking on the Apalachicola-Chattahoochee-Flint (ACF) river system, and evaluating post-stocking success. 3. Completed a survey to document the extent of aquatic resources, recreational fishing opportunities, and fishery management needs on Department of Defense (DoD) facilities located in Region 4. 4. Continued a project in the Apalachicola River to describe the effects of exceptional drought conditions on freshwater mussel recovery. 5. Initiated a study to locate extant populations of the federally endangered Ochlockonee moccasinshell in the Ochlockonee River Basin. We documented the first live individuals in 14 years. 6. Completed a five-year status review for seven threatened and endangered freshwater mussels in the NEG drainages. 7. Restored Mill Creek to improve habitat for the endangered Okaloosa darter by removing six fish passage barriers and creating approximately 3,000 linear feet of new and regenerated stream channel with floodplain and native vegetation. 8. Completed a fish passage project that connected about 5 miles of habitat in Little Rocky Creek, Eglin Air Force Base, to benefit the Okaloosa darter. 9. Completed a threats analysis to aquatic species in the Chipola River watershed using GIS stream data, aerial imagery, and land cover data. 10. Multiple outreach projects were completed to detail aquatic resource conservation needs and opportunities, including National Fishing Week, Earth Day, several festivals, and school outreach.

Aplicaciones enzimáticas en procesos de conservación y restauración de obras de arte. Consolidación de celulosa

690 p.

Engineering enzyme systems by recombination

Homologous recombination is a source of diversity in both natural and directed evolution. Standing genetic variation that has passed the test of natural selection is combined in new ways, generating functional and sometimes unexpected changes. In this work we evaluate the utility of homologous recombination as a protein engineering tool, both in comparison with and combined with other protein engineering techniques, and apply it to an industrially important enzyme: Hypocrea jecorina Cel5a.

Chapter 1 reviews work over the last five years on protein engineering by recombination. Chapter 2 describes the recombination of Hypocrea jecorina Cel5a endoglucanase with homologous enzymes in order to improve its activity at high temperatures. A chimeric Cel5a that is 10.1 °C more stable than wild-type and hydrolyzes 25% more cellulose at elevated temperatures is reported. Chapter 3 describes an investigation into the synergy of thermostable cellulases that have been engineered by recombination and other methods. An engineered endoglucanase and two engineered cellobiohydrolases synergistically hydrolyzed cellulose at high temperatures, releasing over 200% more reducing sugars over 60 h at their optimal mixture relative to the best mixture of wild-type enzymes. These results provide a framework for engineering cellulolytic enzyme mixtures for the industrial conditions of high temperatures and long incubation times.

In addition to this work on recombination, we explored three other problems in protein engineering. Chapter 4 describes an investigation into replacing enzymes with complex cofactors with simple cofactors, using an E. coli enolase as a model system. Chapter 5 describes engineering broad-spectrum aldehyde resistance in Saccharomyces cerevisiae by evolving an alcohol dehydrogenase simultaneously for activity and promiscuity. Chapter 6 describes an attempt to engineer gene-targeted hypermutagenesis into E. coli to facilitate continuous in vivo selection systems.

Gene enrichment using antibodies to DNA/RNA hybrids : mapping the ribosomal DNA of slime mold and rat

A novel method for gene enrichment has been developed and applied to mapping the rRNA genes of two eucaryotic organisms. The method makes use of antibodies to DNA/RNA hybrids prepared by injecting rabbits with the synthetic hybrid poly(rA)•poly(dT). Antibodies which cross-react with non-hybrid nucleic acids were removed from the purified IgG fraction by adsorption on columns of DNA-Sepharose, oligo(dT)-cellulose, and poly(rA)-Sepharose. Subsequent purification of the specific DNA/RNA hybrid antibody was carried out on a column of oligo(dT)-cellulose to which poly(rA) was hybridized. Attachment of these antibodies to CNBr-activated Sepharose produced an affinity resin which specifically binds DNA/RNA hybrids.

In order to map the rDNA of the slime mold Dictyostelium discoideum, R-loops were formed using unsheared nuclear DNA and the 178 and 268 rRNAs of this organism. This mixture was passed through a column containing the affinity resin, and bound molecules containing R- loops were eluted by high salt. This purified rDN A was observed directly in the electron microscope. Evidence was obtained that there is a physical end to Dictyostelium rDN A molecules approximately 10 kilobase pairs (kbp) from the region which codes for the 268 rRNA. This finding is consistent with reports of other investigators that the rRNA genes exist as inverse repeats on extra-chromosomal molecules of DNA unattached to the remainder of the nuclear DNA in this organism.

The same general procedure was used to map the rRNA genes of the rat. Molecules of DNA which contained R-loops formed with the 188 and 288 rRNAs were enriched approximately 150- fold from total genomal rat DNA by two cycles of purification on the affinity column. Electron microscopic measurements of these molecules enabled the construction of an R-loop map of rat rDNA. Eleven of the observed molecules contained three or four R-loops or else two R-loops separated by a long spacer. These observations indicated that the rat rRNA genes are arranged as tandem repeats. The mean length of the repeating units was 37.2 kbp with a standard deviation of 1.3 kbp. These eleven molecules may represent repeating units of exactly the same length within the errors of the measurements, although a certain degree of length heterogeneity cannot be ruled out. If significantly shorter or longer repeating units exist, they are probably much less common than the 37.2 kbp unit.

The last section of the thesis describes the production of antibodies to non-histone chromosomal proteins which have been exposed to the ionic detergent sodium dodecyl sulfate (SDS). The presence of low concentrations of SDS did not seem to affect either production of antibodies or their general specificity. Also, a technique is described for the in situ immunofluorescent detection of protein antigens in polyacrylamide gels.

Estrategias de arranque de biofiltros orgánicos para el tratamiento de corrientes gaseosas contaminadas con compuestos de azufre

[ES]El disulfuro de carbono (CS2) y el sulfuro de hidrógeno (H2S) son gases especialmente tóxicos presentes en una gran cantidad de emisiones gaseosas industriales, principalmente en la producción de fibras de rayón a partir de celulosa en el caso del CS2, y en la industria petroquímica en el caso del H2S. La legislación vigente en cuanto a las emisiones de estos compuestos se refiere hace que su tratamiento sea, en muchos casos, necesario. La biofiltración como tecnología para el tratamiento de corrientes gaseosas contaminadas se ha convertido en los últimos años en una alternativa a los tratamientos físico-químicos empleados hasta la fecha. Sin embargo, uno de los principales obstáculos a la hora de la implantación de este tratamiento biológico a escala industrial es la duración del periodo de aclimatación de la biomasa encargada de degradar los contaminantes, que en función del compuesto a tratar puede resultar demasiado largo para la aplicación comercial de esta tecnología. El presente trabajo se centra en el estudio de estos periodos de arranque y aclimatación, especialmente lentos en el caso del CS2, y propone una estrategia de arranque basada en la reutilización de biomasa capaz de degradar los compuestos de interés, almacenada tras usos anteriores, que permite reducir el tiempo necesario para alcanzar eficacias de eliminación elevadas. Paralelamente, se ha concluido que paradas de corta duración no afectan de manera importante a la operación del sistema.

Flexible microimplants for in vivo sensing

The work in this thesis develops two types of microimplants for the application of cardiovascular in vivo biomedical sensing, one for short-term diagnosis and the other for long-term monitoring.

Despite advances in diagnosis and therapy, atherosclerotic cardiovascular disease remains the leading cause of morbidity and mortality in the Western world. Predicting metabolically active atherosclerotic plaques has remained an unmet clinical need. A stretchable impedance sensor manifested as a pair of quasi-concentric microelectrodes was developed to detect unstable intravascular. By integrating the impedance sensor with a cardiac catheter, high-resolution Electrochemical Impedance Spectroscopy (EIS) measurements can be conducted during cardiac catheterization. An inflatable silicone balloon is added to the sensor to secure a well-controlled contact with the plaque under test in vivo. By deploying the device to the explants of NZW rabbit aorta and live animals, distinct EIS measurements were observed for unstable atherosclerotic plaques that harbored active lipids and inflammatory cells.

On the other hand, zebrafish (Danio rerio) is an emerging genetic model for heart regenerative medicine. In humans, myocardial infarction results in the irreversible loss of cardiomyocytes. Zebrafish hearts can fully regenerate after two months with 20% ventricular resection. Long-term electrocardiogram (ECG) recording can characterize the heart regeneration in a functional dimension. A flexible microelectrode membrane was developed to be percutaneously implanted onto a zebrafish heart and record epicardial ECG signals from specific regions on it. Region-specific aberrant cardiac signals were obtained from injured and regenerated hearts. Following that, in order to achieve continuous and wireless recording from non-sedated and non-restricted small animal models, a wireless ECG recording system was designed for the microelectrode membrane, prototyped on a printed circuit board and demonstrated on a one-day-old neonatal mouse. Furthermore, a flexible and compact parylene C printed circuit membrane was used as the integration platform for the wireless ECG recording electronics. A substantially miniature wireless ECG recording system was achieved.

Guía de diseño de un edificio de bajo consumo energético

[ES]Comparativa de las alternativas disponibles para la construcción de un edificio, con el objetivo de optimizar el diseño disminuyendo las pérdidas de energía. De los distintos tipos de construcciones posibles, la investigación se centra en una vivienda unifamiliar. El trabajo aborda, por una parte, el diseño de la envolvente de la vivienda con las técnicas eficientes y los materiales mejor ajustados a la zona de edificación; y por otra, la selección del sistema de calefacción y de agua caliente sanitaria (ACS). Se opta por bloques de tierra comprimida, aislante de celulosa y enlucido de arcilla para las paredes, así como por una caldera de pellets para el sistema de calefacción y una instalación de energía solar térmica para el ACS.

Síntese, caracterização e avaliação de materiais poliméricos com propriedades bactericidas

Nesta dissertação, foram preparados materiais poliméricos com atividade bactericida a partir de copolímeros de estireno (Sty) e divinilbenzeno (DVB) e de celulose bacteriana. Três copolímeros à base de Sty e DVB foram sintetizados através da técnica de polimerização em suspensão aquosa. Os copolímeros foram preparados com diferentes estruturas porosas, por meio da variação da composição do sistema diluente. Um copolímero comercial macrorreticulado, Amberlite XAD4, de elevada área superficial, também foi usado neste estudo com o objetivo de comparar sua estrutura polimérica e seu desempenho com o dos copolímeros sintetizados. Os copolímeros de Sty-DVB foram caracterizados por meio da densidade aparente, área específica, diâmetro médio de poros, volume de poros, microscopias ótica e eletrônica de varredura, grau de inchamento, espectrometria de infravermelho com transformada de Fourier (FTIR), análise termogravimétrica e análise elementar. Os copolímeros de Sty-DVB foram modificados quimicamente através da reação de nitração, seguida da reação de redução do grupo nitro a amino e posterior reação de diazotação e hidrólise do grupo sal de diazônio. Os copolímeros modificados contendo os grupos NH2 e OH foram utilizados como suporte para a ancoragem das nanopartículas de prata. As partículas de prata foram obtidas pela redução dos íons Ag+ empregando-se cloridrato de hidroxilamina como redutor e PVP como protetor de colóide. O teor de prata impregnada foi determinado pelo método volumétrico. A celulose bacteriana (BC) foi empregada como uma matriz para impregnação de nanopartículas de prata. Membranas de BC foram impregnadas com solução aquosa de AgNO3, a seguir foi realizada a redução dos íons Ag+ com três diferentes agentes redutores (hidrazina, hidroxilamina e ácido ascórbico) empregando ou não protetor de colóide (PVP ou gelatina). As membranas de BC/Ag0 obtidas foram caracterizadas por difração de raios-X, análise termogravimétrica e microscopia eletrônica de varredura. A capacidade bactericida dos copolímeros de Sty-DVB, dos copolímeros funcionalizados e impregnados com prata e das membranas de BC/Ag0 foi avaliada através do método da contagem em placa contra suspensões de Escherichia coli, em diferentes concentrações (103 a 107 células/mL). Foi observado que os copolímeros de origem e os copolímeros modificados contendo os grupos NO2 e NH2 não apresentaram atividade bactericida contra suspensões de E. coli em nenhuma concentração. Por outro lado, os copolímeros modificados contendo o grupo OH apresentaram alguma atividade bactericida, embora abaixo do esperado devido à baixa incorporação de hidroxilas fenólicas. Os copolímeros modificados impregnados com Ag apresentaram maior ação bactericida do que os copolímeros modificados, o que comprova que a ação bactericida é devida às partículas de prata ancoradas nos copolímeros. Os copolímeros modificados contendo o grupo OH impregnados com Ag mesmo possuindo menores teores de prata apresentaram maior ação bactericida do que os copolímeros modificados contendo o grupo NH2 impregnados com Ag. A maior ação bactericida pode ser atribuída à combinação da atividade bactericida das partículas de prata com a atividade dos grupos hidroxilas fenólicas mesmo que estes grupos estejam pouco incorporados nos copolímeros. Os compósitos de BC/Ag0 exibiram atividade bactericida contra E. coli que foi atribuída à ação das nanoparticulas de prata obtidas quando foi empregada a hidroxilamina como agente redutor e a gelatina como protetor de colóide

Avaliação da influência do material de confecção das matrizes no teste de conversão monomérica por espectrometria no infravermelho de um compósito

Este estudo teve por objetivo avaliar, in vitro, a influência do material de confecção das matrizes, traçando um perfil da conversão monomérica de um compósito micro-híbrido, além de avaliar qual dos materiais testados mais se assemelha a uma matriz de dentina. A avaliação foi feita através da análise do grau de conversão (GC). Foram confeccionadas 3 matrizes bipartidas, sendo estas de teflon negro, tefon branco e aço inoxidável, ambas com 10mm de diâmetro e 2 mm de profundidade. Para o grupo controle foi utilizado um incisivo central bovino, o qual teve sua face vestibular aplainada em uma lixadeira sob refrigeração constante, com o auxílio de uma lixa de carbeto de silício, número 800. Após, este dente foi preparado com uma broca diamantada número 2294 (KG Sorensen) em alta rotação, própria para a preparação de cavidades padronizadas para ensaios de laboratório, apresentando um limitador de penetração. Em seguida, com um motor de baixa rotação foi realizado o acabamento das paredes, obtendo-se uma cavidade de 2,0 mm de profundidade por 9,0 mm de diâmetro. Pela palatina desse dente, com uma broca carbide cilíndrica de numeração 2056 (KG Sorensen), fez-se uma penetração até se obter uma parede de dentina extremamente fina, porém sem que esta fosse rompida. Assim, com uma agulha, fez-se uma pequena perfuração no centro dessa dentina para que este instrumental servisse como um pino para remoção do corpo de prova de dentro da matriz de dente. Os corpos de prova (CP) foram obtidos a partir da inserção do compósito no interior da perfuração das matrizes em um único incremento e cobertos na superfície externa com uma matriz de poliéster mais uma lamínula de vidro. Os CP foram fotopolimerizados por 40 s pela fonte de luz halógena Optilux 501 (Demetron), com 500 mW/cm. Imediatamente após a polimerização, os corpos de prova eram submetidos no topo e na base para a análise de espectrometria no infravermelho para a determinação da profundidade de polimerização, pela técnica do filme vazado para o compósito não polimerizado e pela técnica da pastilha de brometo de potássio (KBr) para o compósito polimerizado. Foram confeccionados 5 CP de cada grupo. Em cada grupo, o compósito da base e do topo das amostras foi moído até se obter de 1,5 a 2,0 mg de pó e misturado com 70 mg de KBr, para obtenção da pastilha de KBr. Foi feita a análise de espectrofotometria no infravermelho por Transformada de Fourier (FTIR). As absorções selecionadas para o cálculo foram 1610 cm-1 e 1637 cm-1, os picos dos espectros das ligações dos carbonos aromáticos e alifáticos, respectivamente. Os dados obtidos foram tratados estatisticamente. Os grupos Gr1B, Gr2B, Gr3B e Gr4B representam, respectivamente, as bases dos CP confeccionados pelas matrizes de DB, TN, TB e AI. Já os Gr1T, Gr2T, Gr3T e Gr4T representam os topos. Médias (%) e DP: Gr1T (46,461,99), Gr2T (39,864,51), Gr3T (44,053,44) e Gr4T (38,045,08). Gr1B (40,441,49), Gr2B (36,153,81), Gr3B (40,093,18) e Gr4B (35,593,35). Em posse dos resultados, pôde-se concluir que os grupos do teflon negro, teflon branco e aço inoxidável não apresentaram diferenças entre o grau de conversão do topo e da base, enquanto que o grupo da dentina apresentou maior conversão do topo. Comparando as matrizes entre elas, pôde-se perceber que no topo, o GC do dente bovino é maior que o GC do aço inoxidável e do que o de teflon negro, o GC do teflon branco é maior que o GC do aço inoxidável e do que o de teflon negro. Já o topo dos grupos de dente bovino e teflon banco foram semelhantes. Nas bases dos CPs, não houve diferença significativa entre os grupos testados. De acordo com os resultados obtidos no experimento, pôde-se concluir que nos grupos do teflon negro, teflon branco e aço inoxidável não houve diferença entre 0 e 2 mm, ou seja, topo e base, o que mostra que o material de confecção da matriz não influênciou o grau de conversão do compósito. Já para o grupo da matriz de dentina, o topo apresentou valor de conversão monomérica maior, mostrando que, neste caso, o material da matriz interferiu no grau de conversão. Pode-se perceber também que existe uma tendência da matriz de teflon branco se assemelhar mais a matriz de dentina, pois foi o único grupo que apresentou semelhança nos valores de conversão monomérica no topo das amostras. Porém analisando a base das amostras, percebe-se que todos os grupos se comportaram de forma semelhante, obtendo valores do grau de conversão sem diferença significante.

Efectos de la salinidad y el herbicida glifosato sobre la especie invasora Baccharis halimifolia

CASTELLANO. La introducción de especies exóticas invasoras es una de las causas más importantes de pérdida de biodiversidad. Baccharis halimifolia es una de las 20 especies exóticas invasoras mas perjudiciales en España e invade gran parte de la marisma de Urdaibai. En dicha marisma se aplicaron tratamientos de control mediante la corta y aplicación de herbicida (glifosato) tras los cuales se observó un variable porcentaje de rebrote en función de la salinidad edáfica. Se realizó un experimento en el que las plantas recolectadas en las parcelas tratadas fueron sometidas en el invernadero a un tratamiento de salinidad y a otro de glifosato con el fin de estudiar la interacción entre ambos tratamientos en individuos originados por germinación y por rebrote y las posibles diferencias entre sexos. Se estudiaron los parámetros de biomasa y acumulación de iones sodio. No se han observado diferencias significativas entre los sexos para ninguno de los parámetros. Sin embargo, los rebrotes acumulan más Na+ que los individuos procedentes de germinación y su biomasa disminuye significativamente tras la aplicación de glifosato, únicamente en medio no salino. Nuestros resultados sugieren que los rebrotes de B. halimifolia reaccionan en mayor medida a la salinidad y al glifosato, lo que proporciona información de interés para la gestión.