Estudo da variação de propriedades de geomembranas de PVC devido a danos mecânicos

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2015.

Representaciones sociales y prácticas de actividad física en docentes de educación física, localidad de Suba UPZ 71

Debido a la problemática del sedentarismo e inactividad física en edad escolar y sus implicaciones en la aparición de enfermedades crónicas no transmisibles, surge un interés por realizar análisis cualitativos que tengan en cuenta los contextos sociales en los que se da esta problemática, con el objetivo de conocer, desde los actores inmersos en las comunidades, cómo se está llevando a cabo y cómo se entiende la actividad física; por tanto, se planteó en esta investigación un diseño narrativo en el cual se indagó, por medio de entrevistas a profundidad, acerca de las representaciones sociales y prácticas de actividad física que desarrollan 9 docentes de educación física pertenecientes a 3 colegios distritales de la Unidad de Planeamiento Zonal Tibabuyes, en la localidad de Suba en Bogotá, Colombia. Resultados: Los docentes entienden la actividad física como todo tipo de movimiento humano, así mismo, se evidencia que las prácticas deportivas son las que predominan en el ámbito escolar. En relación con las condiciones sociales, se encontró que el aspecto familiar es un limitante para el desarrollo de las prácticas físicas del estudiante. Las políticas escolares y distritales le restan importancia a las clases de educación física en el currículo escolar y la inseguridad, debido al consumo de sustancias psicoactivas en el sector, deteriora los espacios deportivos y recreativos como parques y zonas verdes.

Etapas de cambio comportamental frente al consumo de drogas ilegales, tabaco y alcohol en escolares de 9 a 17 años de Bogotá – Colombia

Objetivo: El propósito del estudio fue describir estadísticamente las etapas de cambio comportamental frente al consumo de sustancias psicoactivas –SPA– (alcohol, tabaco y drogas ilegales) en escolares entre 9 y 17 años de Bogotá- Colombia, pertenecientes al estudio FUPRECOL. Método: Se trata de un estudio descriptivo y transversal en 6.965 niños y adolescentes entre 9 y 17 años, pertenecientes a 24 instituciones educativas oficiales de Bogotá - Colombia. La medición de los procesos de cambio propuestos por el Modelo Transteórico (MTT), aplicados al consumo de drogas, tabaco y alcohol se aplicaron de manera auto-diligenciada mediante un cuestionario estructurado. Resultados: De la muestra evaluada, el 58,4% fueron mujeres con un promedio de edad 12,74 ± 2.38 años. En la población en general, frente al consumo de drogas, el 6% de los escolares se encontraban en etapa de pre-contemplación, 44 % en contemplación; 30% en preparación/acción, 20% en mantenimiento. Con relación al consumo de alcohol, el 5% de los niños y adolescentes se encontraban en etapa de pre-contemplación, 36 % en contemplación; 12% en preparación/acción, 46% en mantenimiento. Frente al tabaco, el 4% de los niños y adolescentes se encontraban en etapa de pre-contemplación, 33 % en contemplación; 12% en preparación/acción, 51% en mantenimiento. Conclusiones: En los escolares evaluados, un importante porcentaje se ubica en la etapa de mantenimiento frente a la intención de consumo de tabaco y alcohol. Frente al consumo de drogas ilegales los niños y adolescentes están en la etapa de contemplación. Se requieren esfuerzos mayores para fomentar programas preventivos que enseñen sobre el riesgo del abuso/dependencia de este tipo de sustancias psicoactiva sobre la salud; dándole prioridad en las agendas y políticas públicas dentro del ámbito escolar.

Humified fraction of organic matter due to plant mixture cultivation.

The aim of this study was to assess the organic matter changes in quantity and quality, particularly of the humic fraction in the surface layer (0?20 cm), of a Typic Plinthustalf soil under different management of plant mixtures used as green manure for mango (Mangifera indica L.) crops. The plant mixtures, which were seeded between rows of mango trees, were formed by two groups of leguminous and non -leguminous plants. Prior to sowing, seeds were combined in different proportions and compositions constituting the following treatments: 100% non-leguminous species (NL); 100% leguminous species (L); 75% L and 25% NL; 50% L and 50% NL; 25% L and 75% NL; and 100% spontaneous vegetation, considered a control. The plant mixtures that grew between rows of mango trees caused changes in the chemical composition of the soil organic matter, especially for the treatments 50% L and 50% NL and 25% L and 75% NL, which increased the content of humic substances in the soil organic matter. However, the treatment 25% L and 75% NL was best at minimising loss of total organic carbon from the soil. The humic acids studied have mostly aliphatic characteristics, showing large amounts of carboxylic and nitrogen groups and indicating that most of the organic carbon was formed by humic substances, with fulvic acid dominating among the alkali soluble fractions.

The Various of Complete Feed Block for Dairy Cattle

Abstract. The effect of three forms of complete feed blocks (CFB) for dairy cattle was evaluated. The form of various CFB were cube, cylinder and ball.  The CFB was prepared from napier grass specific tolerance acid soils and concentrate in 50:50 ratio.  The research used experimental method with randomized block design.   Sixteen dairy cattle were used in this experiment.  There were four treatments and four replications used in this experiment.  The treatments consisted of R0= control ration, R1= cube CFB, R2= cylinder CFB and R3= ball CFB.  The treatment feeds were fed twice a day, at 6.00 am and 15.00 pm.  The amount of morning ration 34 kg of fresh napier grass and 5 kg of concentrate for the control ration, and the same amount of ration was also given in the afternoon feeding, therefore, the daily total fresh forage was 68 kg and concentrate was 10 kg.  Before feeding the forage was chopped in 5 cm length.  The complete feed block for the dairy cows was 10 kg for the morning ration and 10 kg for the afternoon ration, therefore, the daily total complete feed block was 20 kg.  The drinking water was available adlibitum.  The preliminary period was conducted for 2 weeks and data collection were conducted for 5 day of the end of study. The variables measured were dry matter and organic matter intake, dry matter digestibility and milk production.  These results showed that the control ration significantly affected with  ration all CFB form on dry matter and organic matter intake but did not significantly affect the dry matter digestibility and milk production. Key words : dairy cttle, complete feed block Abstrak.Penelitian ini bertujuan mengevaluasi pengaruh tiga pakan komplit bentuk cetak yaitu bentuk kubus, silinder dan bola yang diberikan pada sapi perah.   Pakan komplit bentuk cetak dibuat dari hijauan rumput gajah yang spesifik toleran tanah masam yang telah digiling dan bahan konsentrat dengan perbandingan 50:50.  Rancangan percobaan yang digunakan adalah rancangan acak kelompok.  Enam belas ekor sapi perah dikelompokkan menjadi 4 dengan 4 ulangan.  Empat perlakuan yang dicobakan yaitu R0= ransum kontrol, R1= pakan komplit cetak bentuk kubus, R2= pakan komplit cetak bentuk silinder, dan R3= pakan komplit cetak bentuk bola. Pakan perlakuan diberikan dua kali sehari pagi pukul 06.00 dan sore 15.00.  Jumlah pakan  yang diberikan pada sapi perah kontrol pagi sebanyak 34 kg rumput gajah segar dan 5 kg konsentrat demikian juga pemberian yang sama pada sore hari sehingga jumlah hijauan segar yang diberikan kepada ternak 68 kg dan konsentrat 10 kg.  Rumput gajah yang diberikan sudah dipotong-potong terlebih dahulu dengan panjang 5 cm.  Jumlah pakan komplit cetak untuk sapi perah perlakuan yang diberikan pagi jumlahnya sama dengan pemberian sore masing-masing sebanyak 10 kg sehingga jumlah pakan komplit cetak yang diberikan 20 kg.  Air minum diberikan adlibitum.  Periode preliminary dilakukan selama 2 minggu dan koleksi data dilakukan selama 5 hari periode akhir percobaan.  Variabel yang diamati adalah konsumsi bahan kering dan bahan organik pakan, kecernaan bahan kering pakan dan produksi susu.  Hasil penelitian menunjukkan bahwa ransum kontrol beda nyata dengan semua bentuk pakan komplit cetak pada konsumsi bahan kering dan bahan organik, akan tetapi tidak berbeda nyata dengan  kecernaan bahan kering dan produksi susu. Kata kunci : sapi perah, pakan komplit bentuk cetak

Characterisation of soils containing naturally occurring radioactive material (NORM) using in situ and rapid laboratory techniques. Case study: South Terras, Cornwall

In situ analysis has become increasingly important for contaminated land investigation and remediation. At present, portable techniques are used mainly as scanning tools to assess the spread and magnitude of the contamination, and are an adjunct to conventional laboratory analyses. A site in Cornwall, containing naturally occurring radioactive material (NORM), provided an opportunity for Reading University PhD student Anna Kutner to compare analytical data collected in situ with data generated by laboratory-based methods. The preliminary results in this paper extend the author‟s poster presentation at last September‟s GeoSpec2010 conference held in Lancaster.

Peat humic substances enriched with nutrients for agricultural applications: Competition between nutrients and non-essential metals present in tropical soils

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Peat humic substances enriched with nutrients for agricultural applications: competion between nutrients and non-essential metals present in tropical soils

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Peat humic substances enriched with nutrients for agricultural applications: Competition between nutrients and non-essential metals present in tropical soils

Improved agricultural productivity, and reduction of environmental impacts, require studies of the interactions between different soil components. Fertilizers marketed as "organic" or "natural", such as peats or humic substances (HS) extracted from peats, are enriched with macro and micronutrients that, according to the manufacturers, are released to the plant in accordance with its needs. This work investigates the complexation capacity of HS for macro and micronutrient metal species, considering the competition, for HS complexation sites, between non-essential metals (aluminium and lead), present in the soil, and the nutrients. Humic substances were found to possess strong affinities for Pb(II) and Al(III), forming stable complexes, with concomitant release of complexed nutrients. Although HS are already used commercially as organic fertilizers, further studies of methods of HS enrichment, aimed at avoiding losses, are highly desirable from environmental and economic perspectives. (C) 2009 Elsevier B.V. All rights reserved.

Analytical method development for the uptake study of different organic pollutants by crops cultivated in compost-amended soils

256 p.

Thiram in the environment: effect of humic substances and Cu(II) ions

Em Portugal, o tirame é um dos fungicidas mais utilizados, cujas vendas aumentaram significativamente nos últimos anos, sendo também um dos fungicidas mais utilizados em todo o mundo. No entanto, em comparação com outros pesticidas, existe falta de informação na literatura sobre o seu comportamento em sistemas ambientais, nomeadamente, no que diz respeito à sua degradação no solo ou em águas e produtos a que dá origem. Neste contexto, o objetivo deste trabalho foi estudar a influência das substâncias húmicas e iões cobre no comportamento e destino do tirame no meio ambiente. Foram realizados vários estudos para analisar o comportamento do tirame em solos com diferentes conteúdos de matéria orgânica e de iões cobre, e em águas naturais, estudando como as substâncias húmicas, os iões cobre e a luz solar podem afetar a sua degradação. Os estudos de adsorção-desadsorção do tirame nos solos revelaram que a matéria orgânica do solo e o conteúdo de cobre afetavam os processos de adsorção-desadsorção do tirame, influenciando a sua lixiviação e persistência no solo. De facto, verificou-se que o teor de cobre do solo tinha um efeito bastante marcante no processo de adsorçãodesadsorção do tirame. Verificou-se a ocorrência de reações entre o tirame e os iões cobre, cuja extensão durante os estudos de adsorção pode ser fortemente dependente do teor de cobre do solo e da concentração inicial de tirame em solução. Assim, a escolha do tempo de equilíbrio em estudos de adsorção e a determinação das isotérmicas de adsorção ao solo torna-se uma tarefa difícil. Além disso, os complexos formados com o cobre existente no solo são persistentes, não sendo facilmente lixiviados para as águas subterrâneas. Conclui-se que os iões cobre(II) podem contribuir para a imobilização do tirame no solo e o aumento da persistência dos seus resíduos ligados ao cobre. A partir de estudos de recuperação do tirame em águas naturais verificou-se a ocorrência de uma rápida degradação do tirame, devido provavelmente aos iões metálicos, nomeadamente, iões cobre. Verificou-se que dependendo da razão tirame:Cu podiam ocorrer dois processos: (i) complexação entre o tirame e o cobre, quando não há excesso de iões cobre, sendo o complexo formado mais persistente que o tirame; (ii) ou, quando há um grande excesso de iões cobre, a degradação do tirame e a estabilização dos produtos de degradação por complexação, podendo formar-se complexos que permanecem sem alteração em solução durante pelo menos dois meses. No geral, foi possível, pela primeira vez, identificar alguns dos complexos de cobre formados ao longo do tempo. Por fim, estudou-se a cinética de fotodegradação do tirame em solução aquosa sob a ação da luz solar e identificaram-se, pela primeira vez, três fotoprodutos. Verificou-se um aumento da velocidade de fotodegradação do tirame na presença de substâncias húmicas. Assim, podemos concluir que a matéria orgânica, os iões cobre(II) e a luz solar têm um efeito importante no comportamento do tirame no meio ambiente. Contudo, os iões cobre têm um efeito mais marcante na degradação e persistência dos produtos que são formados.

Pollution and pollutant transport in the geosphere - An introduction to the symposium

Environmental research in earth sciences is focused on the geosphere, i.e. (1) waters and sediments of rivers, lakes and oceans, and (2) soils and underlying shallow rock formations,both water-unsaturated and -saturated. The subsurface is studied down to greater depths at sites where waste repositories or tunnels are planned and mining activities exist. In recent years, earth scientists have become more and more involved in pollution problems related to their classical field of interest, e.g. groundwater, ore deposits, or petroleum and non-metal natural deposits (gravel, clay, cement precursors). Major pollutants include chemical substances, radioactive isotopes and microorganisms. Mechanisms which govern the transport of pollutants are of physical, chemical (dissolution, precipitation, adsorption), or microbiological (transformation) nature. Land-use planning must reflect a sustainable development and sound scientific criteria. Today's environmental pollution requires working teams with an interdisciplinary background in earth sciences, hydrology, chemistry, biology, physics as well as engineering. This symposium brought together for the first time in Switzerland earth and soil scientists, physicists and chemists, to present and discuss environmental issues concerning the geosphere.

Composition and stability of organic matter fractions in soils under different land use regimes

Soil organic matter (SOM) vitally impacts all soil functions and plays a key role in the global carbon (C) cycle. More than 70% of the terrestric C stocks that participate in the active C cycle are stored in the soil. Therefore, quantitative knowledge of the rates of C incorporation into SOM fractions of different residence time is crucial to understand and predict the sequestration and stabilization of soil organic carbon (SOC). Consequently, there is a need of fractionation procedures that are capable of isolating functionally SOM fractions, i.e. fractions that are defined by their stability. The literature generally refers to three main mechanisms of SOM stabilization: protection of SOM from decomposition by (i) its structural composition, i.e. recalcitrance, (ii) spatial inaccessibility and/or (iii) interaction with soil minerals and metal ions. One of the difficulties in developing fractionation procedures for the isolation of functional SOM fractions is the marked heterogeneity of the soil environment with its various stabilization mechanisms – often several mechanisms operating simultaneously – in soils and soil horizons of different texture and mineralogy. The overall objective of the present thesis was to evaluate present fractionation techniques and to get a better understanding of the factors of SOM sequestration and stabilization. The first part of this study is attended to the structural composition of SOM. Using 13C cross-polarization magic-angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy, (i) the effect of land use on SOM composition was investigated and (ii) examined whether SOM composition contributes to the different stability of SOM in density and aggregate fractions. The second part of the present work deals with the mineral-associated SOM fraction. The aim was (iii) to evaluate the suitability of chemical fractionation procedures used in the literature for the isolation of stable SOM pools (stepwise hydrolysis, treatments using oxidizing agents like Na2S2O8, H2O2, and NaOCl as well as demineralization of the residue obtained by the NaOCl treatment using HF (NaOCl+HF)) by pool sizes, 13C and 14C data. Further, (iv) the isolated SOM fractions were compared to the inert organic matter (IOM) pool obtained for the investigated soils using the Rothamsted Carbon Model and isotope data in order to see whether the tested chemical fractionation methods produce SOM fractions capable to represent this pool. Besides chemical fractionation, (v) the suitability of thermal oxidation at different temperatures for obtaining stable SOC pools was evaluated. Finally, (vi) the short-term aggregate dynamics and the factors that impact macroaggregate formation and C stabilization were investigated by means of an incubation study using treatments with and without application of 15N labeled maize straw of different degradability (leaves and coarse roots). All treatments were conducted with and without the addition of fungicide. Two study sites with different soil properties and land managements were chosen for these investigations. The first one, located at Rotthalmünster, is a Stagnic Luvisol (silty loam) under different land use regimes. The Ah horizons of a spruce forest and continuous grassland and the Ap and E horizons of two plots with arable crops (continuous maize and wheat cropping) were examined. The soil of the second study site, located at Halle, is a Haplic Phaeozem (loamy sand) where the Ap horizons of two plots with arable crops (continuous maize and rye cropping) were investigated. Both study sites had a C3-/C4-vegetational change on the maize plot for the purpose of tracing the incorporation of the younger, maize-derived C into different SOM fractions and the calculation of apparent C turnover times of these. The Halle site is located near a train station and industrial areas, which caused a contamination with high amounts of fossil C. The investigation of aggregate and density fractions by 13C CPMAS NMR spectroscopy revealed that density fractionation isolated SOM fractions of different composition. The consumption of a considerable part (10–20%) of the easily available O-alkyl-C and the selective preservation of the more recalcitrant alkyl-C when passing from litter to the different particulate organic matter (POM) fractions suggest that density fractionation was able to isolate SOM fractions with different degrees of decomposition. The spectra of the aggregate fractions resembled those of the mineral-associated SOM fraction obtained by density fractionation and no considerable differences were observed between aggregate size classes. Comparison of plant litter, density and aggregate size fractions from soil under different land use showed that the type of land use markedly influenced the composition of SOM. While SOM of the acid forest soil was characterized by a large content (> 50%) of POM, which contained high amounts of spruce-litter derived alkyl-C, the organic matter in the biologically more active grassland and arable soils was dominated by mineral-associated SOM (> 95%). This SOM fraction comprised greater proportions of aryl- and carbonyl-C and is considered to contain a higher amount of microbially-derived organic substances. Land use can alter both, structure and stability of SOM fractions. All applied chemical treatments induced considerable SOC losses (> 70–95% of mineral-associated SOM) in the investigated soils. The proportion of residual C after chemical fractionation was largest in the arable Ap and E horizons and increased with decreasing C content in the initial SOC after stepwise hydrolysis as well as after the oxidative treatments with H2O2 and Na2S2O8. This can be expected for a functional stable pool of SOM, because it is assumed that the more easily available part of SOC is consumed first if C inputs decrease. All chemical treatments led to a preferential loss of the younger, maize-derived SOC, but this was most pronounced after the treatments with Na2S2O8 and H2O2. After all chemical fractionations, the mean 14C ages of SOC were higher than in the mineral-associated SOM fraction for both study sites and increased in the order: NaOCl < NaOCl+HF ≤ stepwise hydrolysis << H2O2 ≈ Na2S2O8. The results suggest that all treatments were capable of isolating a more stable SOM fraction, but the treatments with H2O2 and Na2S2O8 were the most efficient ones. However, none of the chemical fractionation methods was able to fit the IOM pool calculated using the Rothamsted Carbon Model and isotope data. In the evaluation of thermal oxidation for obtaining stable C fractions, SOC losses increased with temperature from 24–48% (200°C) to 100% (500°C). In the Halle maize Ap horizon, losses of the young, maize-derived C were considerably higher than losses of the older C3-derived C, leading to an increase in the apparent C turnover time from 220 years in mineral-associated SOC to 1158 years after thermal oxidation at 300°C. Most likely, the preferential loss of maize-derived C in the Halle soil was caused by the presence of the high amounts of fossil C mentioned above, which make up a relatively large thermally stable C3-C pool in this soil. This agrees with lower overall SOC losses for the Halle Ap horizon compared to the Rotthalmünster Ap horizon. In the Rotthalmünster soil only slightly more maize-derived than C3-derived SOC was removed by thermal oxidation. Apparent C turnover times increased slightly from 58 years in mineral-associated SOC to 77 years after thermal oxidation at 300°C in the Rotthalmünster Ap and from 151 to 247 years in the Rotthalmünster E horizon. This led to the conclusion that thermal oxidation of SOM was not capable of isolating SOM fractions of considerably higher stability. The incubation experiment showed that macroaggregates develop rapidly after the addition of easily available plant residues. Within the first four weeks of incubation, the maximum aggregation was reached in all treatments without addition of fungicide. The formation of water-stable macroaggregates was related to the size of the microbial biomass pool and its activity. Furthermore, fungi were found to be crucial for the development of soil macroaggregates as the formation of water-stable macroaggregates was significantly delayed in the fungicide treated soils. The C concentration in the obtained aggregate fractions decreased with decreasing aggregate size class, which is in line with the aggregate hierarchy postulated by several authors for soils with SOM as the major binding agent. Macroaggregation involved incorporation of large amounts maize-derived organic matter, but macroaggregates did not play the most important role in the stabilization of maize-derived SOM, because of their relatively low amount (less than 10% of the soil mass). Furthermore, the maize-derived organic matter was quickly incorporated into all aggregate size classes. The microaggregate fraction stored the largest quantities of maize-derived C and N – up to 70% of the residual maize-C and -N were stored in this fraction.

Evaluation of optical techniques for characterising soil organic matter quality in agricultural soils

Soil organic matter (SOM) is one of the main global carbon pools. It is a measure of soil quality as its presence increases carbon sequestration and improves physical and chemical soil properties. The determination and characterisation of humic substances gives essential information of the maturity and stresses of soils as well as of their health. However, the determination of the exact nature and molecular structure of these substances has been proven difficult. Several complex techniques exist to characterise SOM and mineralisation and humification processes. One of the more widely accepted for its accuracy is nuclear magnetic resonance (NMR) spectroscopy. Despite its efficacy, NMR needs significant economic resources, equipment, material and time. Proxy measures like the fluorescence index (FI), cold and hot-water extractable carbon (CWC and HWC) and SUVA-254 have the potential to characterise SOM and, in combination, provide qualitative and quantitative data of SOM and its processes. Spanish and British agricultural cambisols were used to measure SOM quality and determine whether similarities were found between optical techniques and 1H NMR results in these two regions with contrasting climatic conditions. High correlations (p < 0.001) were found between the specific aromatic fraction measured with 1H NMR and SUVA-254 (Rs = 0.95) and HWC (Rs = 0.90), which could be described using a linear model. A high correlation between FI and the aromatics fraction measured with 1H NMR (Rs = −0.976) was also observed. In view of our results, optical measures have a potential, in combination, to predict the aromatic fraction of SOM without the need of expensive and time consuming techniques.