El ambiente de aprendizaje del inglés como lengua extranjera y el comportamiento de los estudiantes entre los nueve y doce años de edad de la Fundación ASE

Tesis (Licenciado en Lenguas Castellana, Inglés y Francés).--Universidad de La Salle. Facultad de Ciencias de La Educación. Licenciatura en Lengua Castellana, Inglés y Francés, 2014

Design, construction and evaluation of a simple pressurized solvent extraction system

This work describes the construction and testing of a simple pressurized solvent extraction (PSE) system. A mixture of acetone:water (80:20), 80 ºC and 103.5 bar, was used to extract two herbicides (Diuron and Bromacil) from a sample of polluted soil, followed by identification and quantification by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The system was also used to extract soybean oil (70 ºC and 69 bar) using pentane. The extracted oil was weighed and characterized through the fatty acid methyl ester analysis (myristic (< 0.3%), palmitic (16.3%), stearic (2.8%), oleic (24.5%), linoleic (46.3%), linolenic (9.6%), araquidic (0.3%), gadoleic (< 0.3%), and behenic (0.3%) acids) using high-resolution gas chromatography with flame ionization detection (HRGC-FID). PSE results were compared with those obtained using classical procedures: Soxhlet extraction for the soybean oil and solid-liquid extraction followed by solid-phase extraction (SLE-SPE) for the herbicides. The results showed: 21.25 ± 0.36% (m/m) of oil in the soybeans using the PSE system and 21.55 ± 0.65% (m/m) using the soxhlet extraction system; extraction efficiency (recovery) of herbicides Diuron and Bromacil of 88.7 ± 4.5% and 106.6 ± 8.1%, respectively, using the PSE system, and 96.8 ± 1.0% and 94.2 ± 3.9%, respectively, with the SLP-SPE system; limit of detection (LOD) and limit of quantification (LOQ) for Diuron of 0.012 mg kg-1 and 0.040 mg kg-1, respectively; LOD and LOQ for Bromacil of 0.025 mg kg-1 and 0.083 mg kg-1, respectively. The linearity used ranged from 0.04 to 1.50 mg L-1 for Diuron and from 0.08 to 1.50 mg L-1 for Bromacil. In conclusion, using the PSE system, due to high pressure and temperature, it is possible to make efficient, fast extractions with reduced solvent consumption in an inert atmosphere, which prevents sample and analyte decomposition.

Investigation of a method for predicting AUV derivatives

The paper addresses the problem of autonomous underwater vehicle (AUV) modelling and parameter estimation as a means to predict the dynamic performance of underwater vehicles and thus provide solid guidelines during their design phase. The use of analytical and semi-empirical (ASE) methods to estimate the hydrodynamic derivatives of a popular class of AUVs is discussed. A comparison is done with the results obtained by using computational fluid dynamics to evaluate the bare hull lift force distribution around a fully submerged body. An application is made to the estimation of the hydrodynamic derivatives of the MAYA AUV, an autonomous underwater vehicle developed under a joint Indian-Portuguese project. The estimates obtained were used to predict the turning diameter of the vehicle during sea trials. (C) 2008 Elsevier Ltd. All rights reserved.

Investigation of Normal Force and Moment Coefficients for an AUV at Nonlinear Angle of Attack and Sideslip Range

This paper presents a comparative study of computational fluid dynamics (CFD) and analytical and semiempirical (ASE) methods applied to the prediction of the normal force and moment coefficients of an autonomous underwater vehicle (AUV). Both methods are applied to the. bare hull of the vehicle and to the body-hydroplane combination. The results are validated through experiments in a towing tank. It is shown that the CFD approach allows for a good prediction of the coefficients over the range of angles of attack considered. In contrast with the traditional ASE formulations used in naval and aircraft fields, an improved methodology is introduced that takes advantage of the qualitative information obtained from CFD flow visualizations.

Changes in wood-water relationship due to heat treatment assessed on micro-samples of three Eucalyptus species

Wood-water relationship of untreated and heat-treated wood was studied. Specimens of Eucalyptus grandis, E saligna, and E citriodora were submitted to five conditions of heat treatment: 180 degrees C and 220 degrees C with air; 220 degrees C, 250 degrees C, and 280 degrees C with N(2). The wood-water relationships were accurately studied in a special device, in which the moisture content (MC) of the sample was measured with a highly sensitive electronic microbalance placed in a climatic chamber. The dimensions of the sample were collected continuously without contact by means of two high-speed laser scan micrometers. Sorption curves and shrinkage-MC relationships were observed. To study the effects of heat treatment, the following parameters were also determined: fiber saturation point (FPS), wood anisotropy (T/R ratio), shrinkage slope, reduction in hygroscopicity, and anti-shrink efficiency (ASE). The physical properties were significantly affected only at 220 degrees C and above. At heat temperature levels higher than 220 degrees C, the reduction in hygroscopicity and ASE are higher than 40% and continue to be reduced with increasing temperature level. This work also demonstrates that heat treatment does not change the slope of the curves shrinkage vs. MC, proving that heat treatment affects the domain of alterations in wood properties, but not the behavior within this domain.

Multi-system neurological disease is common in patients with OPA1 mutations

Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal `dominant optic atrophy plus` variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44-6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08-4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment.

A Simple and Efficient Device for Demonstrating Cross-sectional Anatomy of the Head

Described in this article is a novel device that facilitates study of the cross-sectional anatomy of the human head. In designing our device, we aimed to protect sections of the head from the destructive action of handling during anatomy laboratory while also ensuring excellent visualization of the anatomic structures. We used an electric saw to create 15-mm sections of three cadaver heads in the three traditional anatomic planes and inserted each section into a thin, perforated display box made of transparent acrylic material. The thin display boxes with head sections are kept in anatomical order in a larger transparent acrylic storage box containing formaldehyde solution, which preserves the specimens but also permits direct observation of the structures and their anatomic relationships to each other. This box-within-box design allows students to easily view sections of a head in its anatomical position as well as to examine internal structures by manipulating individual display boxes without altering the integrity of the preparations. This methodology for demonstrating cross-section anatomy allows efficient use of cadaveric material and technician time while also giving learners the best possible handling and visualization of complex anatomic structures. Our approach to teaching cross-sectional anatomy of the head can be applied to any part of human body, and the value of our device design will only increase as more complicated understandings of cross-sectional anatomy are required by advances and proliferation of imaging technology. Anat Sci Educ 3: 141-143, 2010. (C) 2010 American Association of Anatomists.

Aplicação da abordagem socioeconómica na Empresa X: corrigir disfunções e potenciar resultados – estudo de caso

Mestrado em Contabilidade

Abordagem integrada na análise química de amostras ambientais

Dissertação para obtenção do Grau de Doutor em Química

Producción de información para las políticas públicas: observatorio de salud mental y derechos humanos en la provincia de córdoba. Documented information and indicators for the pubic policies in mental health: human rights obseratory in córdoba

El problema que enfrenta la institucionalidad estatal argentina es que existe un serio déficit de información no solamente en el momento de evaluar un resultado, sino ya al momento de diseñar la política. Las estadísticas oficiales de hechos vitales, salud y educación son difundidas en el mejor de los casos con un año de atraso. La información de indicadores de salud por su nivel de desagregación no permite conocer las realidades locales. Es posible constatar la falta de información sobre las medidas tomadas para asegurar el cumplimiento de las obligaciones del Estado en lo relativo a políticas y programas de salud mental. Del mismo modo que los organismos internacionales determinan los deficits de los sistemas de atención a la salud mental a través de las brechas de tratamiento y aun cuando no se dispone de estimaciones precisas se habla de brechas de información, que expresarían la distancia entre la información necesaria y la efectivamente disponible (OPS, 2009). Desde el mes de diciembre de 2007 se conforma la Mesa de Trabajo Permanente en Salud Mental y Derechos Humanos, con el objeto de instalar en agenda la necesidad de contar con una legislación que brinde el marco normativo para la transformación del sector. En los meses de octubre y noviembre de 2010 se aprobaron sendas leyes de salud mental en la Provincia de Córdoba y a nivel nacional. Ambas proponen la transformación progresiva en los sistemas de atención a los problemas de salud mental de la población. Desde la Mesa de Trabajo Permanente en Salud Mental y Derechos Humanos se afirma que la legislación es un marco necesario pero no suficiente, en tanto se constata que las princiales violaciones a los derechos humanos se producen en situaciones concretas. El presente proyecto nace de la necesidad de contar con un sistema de información que permita conocer la transformación de los servicios de salud mental en la provincia de Córdoba a partir de la sanción de la ley 9848 de Salud Mental en el mes de octubre de 2010. Una vez logrado este objetivo legislativo, se pretende monitorear la gestión con la formulación de los siguientes interrogantes: ¿a través de qué indicadores medir, evaluar y monitorear si la producción de los servicios de salud mental se lleva adelante desde la perspectiva del enfoque de derechos sancionada en el marco normativo vigente?; ¿cuáles son los indicadores que desde dicha perspectiva los organismos estatales de producción de servicios deben elaborar para el compromiso de acción y la rendición de cuentas frente a la ciudadanía? ¿cuáles son los indicadores que la ciudadanía debe reclamar a los fines de monitorear el cumplimiento de dichos compromisos? La puesta en marcha del Observatorio de Salud Mental y Derechos Humanos permitirá analizar las políticas y programas de salud mental desde la perspectiva de los derechos humanos y avanzar en el monitoreo de la producción de los servicios de salud mental. Objetivo General: analizar y hacer visible el cumplimiento de los objetivos sancionados en la ley 9848 de Salud Mental a través de la observación, el monitoreo y la incidencia en las políticas de salud mental de la provincia de Córdoba. Metodología: la construcción de indicadores de derechos humanos para la salud mental. El Observatorio de Salud Mental y Derechos Humanos pretende dar cuenta de las transformaciones que van a ocurrir a partir de la sanción de la ley 9848. Los resultados esperados están ligados a la producción y difusión de información sistematizada sobre las transformaciones en salud mental, a la vigilancia y el análisis del efecto/impacto de las políticas e incidir en las decisiones. El Observatorio pretende reconocer e integrar la información disponible y proponer indicadores que den cuenta de la situación inicial al momento de la implementación de los marcos normativos y permitir el monitoreo de las transformaciones emergentes. This project stems from the need for an information system designed to show the transformation of mental health services in the province of Cordoba after the enactment of the Mental Health Act 9848 in October 2010. Once achieved this legislative objective is to monitor the management with the formulation of the following questions: through which indicators to measure, evaluate and monitor whether the production of mental health services are carried forward from the perspective of rights-based approach enacted in two laws?, What are the indicators from that perspective the production agencies should develop services for the commitment to action and accountability to the public? What are the indicators that the public should demand that the purpose of monitoring compliance with these commitments? The launch of the Centre for Mental Health and Human Rights will review the policies and mental health programs from the perspective of human rights and progress in monitoring the production of mental health services. General Objective: to analyze and highlight the achievement of the objectives sanctioned by the Mental Health Act 9848 through the observation, monitoring and impact on mental health policy in the province of Cordoba. Methodology: building human rights indicators for mental health Mental Observatory Health and Human Rights aims to account for the changes that will occur after the enactment of Law 9848. The expected results are linked to production and dissemination of systematic information about changes in mental health, surveillance and analysis of the effect / impact and influence policy decisions. The Centre aims to recognize and integrate the available information and propose indicators that account for the initial situation at the time of implementation of regulatory frameworks and allow monitoring of change emerging.

Comparação da adequação de solicitação de ecocardiograma entre hospitais público e privado

FUNDAMENTO: Buscando aprimorar a utilização dos exames de ecocardiografia, foram criados os Critérios de Adequação (CA) (Appropriateness Criteria), pela Sociedade Norte-Americana de Ecocardiografia (ASE) /Colégio Americano de Cardiologia (ACC). OBJETIVO: Comparar o perfil de adequação de solicitação de ecocardiograma transtorácico (ETT) de acordo com os CA, entre Hospital Público Universitário (HU) e Hospital Privado (HP), e verificar quais características se associam com melhor perfil de solicitação de ETT. MÉTODOS: Foram avaliados prospectivamente 779 solicitações consecutivas de ETT no HP (49,8%) e no HU (50,2%). Sendo 55,6% solicitações para mulheres e 44,4%, para homens com 59,1 ± 15,7 anos. As indicações foram classificadas como: apropriadas, inapropriadas ou não classificadas, e a adequação aos CA foi correlacionada com idade, sexo dos pacientes, além do tempo de formado do solicitante. A análise estatística empregou Coeficiente Kappa e teste Qui-quadrado. RESULTADOS: Não houve diferença significativa no perfil de adequação de solicitações apropriadas de ETT nas duas instituições (71% x 75%; p = 0,3). No HP, os fatores associados a maior taxa de exames apropriados foram: sexo feminino (p = 0,001) e idade menor que 60 anos (p < 0,001). No HU, médicos formados entre 5 e 10 anos apresentaram maior taxa de solicitações inadequadas (p = 0,02). As variáveis que foram preditoras independentes de exames apropriados foram, no HP: sexo feminino (p = 0,001) e idade < 60 anos (p = 0,001). CONCLUSÃO: Nesta avaliação, HP e HU apresentaram perfis de adequação de solicitações similares. Sexo feminino, tempo de formado do médico solicitante e a idade do paciente influíram na adequação das solicitações.

Analyse fonctionnelle et moléculaire d'un nouveau gène (VIT32) impliqué dans le mécanisme d'action de la vasopressine

Résumé Les mécanismes de régulation de la réabsorption fine du sodium dans la partie distale (tube distal et tube collecteur) du néphron ont un rôle essentiel dans le maintien de l'homéostasie de la composition ionique et du volume des fluides extracellulaires. Ces mécanismes permettent le maintien de la pression sanguine. Dans la cellule principale du tube collecteur cortical (CCD), le taux de réabsorption de sodium dépend essentiellement de l'activité du canal épithélial à sodium (ENaC) à la membrane apicale et de la pompe sodium-potassium-adénosine-triphosphatase (Na+-K±ATPase) à la membrane basolatérale. L'activité de ces deux molécules de transport est en partie régulée par des hormones dont l'aldostérone, la vasopressine et l'insuline. Dans les cellules principales de CCD, la vasopressine régule le transport de sodium en deux étapes : une étape précoce dite « non-génomique » et une étape tardive dite « génotnique ». Durant l'étape précoce, la vasopressine régule l'expression de gènes, dont certains peuvent être impliqués dans le transport de sodium, comme ENaC et la Na+ -K+ATP ase. Le but de mon travail a été d'étudier l'implication d'une protéine appelée VIP32 (vasopressin induced protein : VIP) dans le transport de sodium. L'expression de VIP32 est augmentée par la vasopressine dans les cellules principales de CCD. Dans l'ovocyte de Xenopus laevis utilisé comme système d'expression hétérologue, nous avons montré que l'expression de VIP32 provoque la maturation méiotique de l'ovocyte par l'activation de la voie des MAPK (mitogen-activated protein kinase : MAPK) et du facteur de promotion méiotique (MPF). La co-expression d'ENaC et de VIP32 diminue l'activité d'ENaC de façon sélective, par l'activation de la voie des MAPK, sans affecter l'expression du canal à la surface membranaire. Nous avons également montré que la régulation de l'activité d'ENaC par la voie des MAPK est dépendante du mécanisme de régulation d'ENaC lié à un motif du canal appelé PY. Ce motif est impliqué dans le contrôle de la probabilité d'ouverture ainsi que l'expression à la surface membranaire d'ENaC. Dans les cellules principales, VIP32 par l'activation de la voie des MAPK peut être impliqué dans la régulation négative du transport transépithélial qui a lieu après plusieurs heures de traitement à la vasopressine. Le tube collecteur de reins normaux présente un taux basal significatif d'activité de la voie MAPK MEK1/2-ERK1/2. Dans la lignée mpkCCDc14 de cellules principales de CCD de souris, que nous avons utilisé pour cette partie du travail, nous avons montré la présence d'un taux basal d'activité d'ERK1/2 (pERK1/2). L'aldostérone et la vasopressine, connus pour stimuler le courant sodique transépithélial dans le CCD, ne changeaient pas le taux basal de pERK1/2. Le transport de sodium transépithélial basal, ou stimulé par l'aldostérone ou la vasopressine est diminué par l'effet de PD98059, un inhibiteur de MEK1/2 qui diminue parallèlement le taux de pERK1/2. Nous avons également montré dans des cellules non stimulées, ou stimulées par de l'aldostérone ou de la vasopressine, que l'activité de la Na+-K+ ATPase, mais pas celle d'ENaC est inhibée par des traitements avec différents inhibiteurs de MEK1/2. Par un marquage de la Na±-K+ATPase à la surface membranaire nous avons montré que la voie d'ERK1/2 contrôle l'activité intrinsèque de la Na+-K+ ATPase, plutôt que son expression à la surface membranaire. Ces données ont montré que l'activité de la Na+-K+ATPase et le transport transépithélial de sodium sont contrôlés par l'activité basal et constitutive de la voie d'ERK1/2. Summary The regulation of sodium reabsorption in the distal nephron (distal tubule and cortical collecting duct) in the kidney plays an essential role in the control of extracellular fluids composition and volume, and thereby blood pressure. In the principal cell of the collecting duct (CCD), the level of sodium reabsorption mainlly depends on the activity of both epithlial sodium channel (ENaC) and sodium-potassium-adenosine-triphosphatase (Na+-K+ATPase). The activity of these two transporters is regulated by hormones especially aldosterone, vasopressin and insuline.In the principal cell of the CCD, vasopressin regulates sodium transport via a short-term effect and a late genomic effect. During the genomic effect vasopressin activates a complex network of vasopressin-dependent genes involved in the regulation of sodium transport as ENaC and Na+-K+ATPase. We were interested in the role of a recently identified vasopressin induced protein (VIP32) and its implication in the regulation of sodium transport in principal cell of the CCD. The Xenopus oocyte expression system revealed two functions : expressed alone VIP32 rapidly induces oocyte meiotic maturation through the activation of the mitogen-activated protein kinase (MAPK) pathway and the meiotic promoting factor and when co-expressed with ENaC, V1P32 selectively dowrn-egulates channel activity, but not channel cell surface expression. We have shown that the ENaC downregulation mediated by the activation of the MAPK pathway is related to the PY motif of ENaC. This motif is implicated in ENaC cell surface expression and open probability regulation. In the kidney principal cell, VIP32 through the activation of MAPK pathway may be involved in the downregulation of transepithelial sodium transport observed within a few hours after vasopressin treatment. The collecting duct of normal kidney exhibits significant activity of the MEK1/2-ERK1/2 MAPK pathway. Using in vitro cultured mpkCCDc14 principal cells we have shown a significant basal level of ERK1/2 activity (pERK1/2). Aldosterone and vasopressin, known to upregulate sodium reabsorption in CCDs, did not change ERK1/2 activity. Basal and aldosterone- or vasopressin-stimulated sodium transport were downregulated by the MEK1/2 inhibitor PD98059 in parallel with a decrease in pERK1/2 in vitro. The activity of Na+-K+ATPase but not that of ENaC was inhibited by MEK1/2 inhibitors in both, unstimulated and aldosterone- or vasopressin-stimulated CCDs in vitro. Cell surface labelling showed that intrinsic activity rather than cell surface expression of Na+-K+ATPase was controlled by pERK1/2. Our data demonstrate that basal constitutive activity of ERK1/2 pathway controls Na+-K+ATPase activity and transepithelial sodium transport in the principal cell. Résumé tout public Les mécanismes de régulation de la réabsorption fine du sodium dans la partie distale du néphron (l'unité fonctionnelle du rein) ont un rôle essentiel dans le maintien de l'homéostasie de la composition et du volume des fluides extracellulaires. Ces mécanismes permettent de maintenir une pression sanguine effective. Dans les cellules principales du tube collecteur, une région spécifique du néphron distal, le transport de sodium dépend essentiellement de l'activité de deux transporteurs de sodium : le canal épithélial à sodium (ENaC) et la pompe sodium-potassium-adénosine-triphosphatase (Na+-K+ATPase). Afin de répondre aux besoins de l'organisme, l'activité de ces deux molécules de transport est en partie régulée par des hormones dont l'aldostérone, la vasopressine et l'insuline. Dans les cellules principales du tube collecteur, la vasopressine régule le transport de sodium en deux étapes : une étape rapide et une étape lente dite « génomique ». Durant l'étape lente, la vasopressine régule l'expression de gènes pouvant être impliqués dans le transport de sodium, dont notamment ceux d'ENaC et de la Na+-K+ATPase. Parmi les gènes dont l'expression est augmentée par la vasopressine, celui de VIP32 (vasopressin induced protein : VIP) fait l'objet de cette étude. Le but de mon travail a été d'étudier, dans un système d'expression hétérologue (l'ovocyte de Xenopus leavis), l'implication de VIP32 dans le transport de sodium. Nous avons montré que VIP32 est capable d'activer un mécanisme moléculaire en cascade appelé MAPK (mitogen-activated protein kinase : MAPK) et est aussi capable de diminuer l'activité d'ENaC. Parallèlement, dans une lignée de cellules principales de tube collecteur les mpkCCDc14, nous avons montré que le taux basal d'activité de la cascade MAPK est capable de réguler l'activité de la Na+-K+ATPase, tandis qu'il n'influence pas l'activité d'ENaC.

Corrimentos vaginais em gestantes: comparacao da abordagem sindromica com exames da pratica clinica da enfermagem

Estudo avaliativo de abordagem quantitativa, com amostra de 104 gestantes, com o objetivo de comparar os achados de infecções vaginais em gestantes obtidos por meio do fluxograma de corrimento vaginal com exames presentes na prática clínica da Enfermagem. Os dados foram coletados por meio de entrevista e exame ginecológico realizados de janeiro a julho de 2011. O fluxograma não se mostrou eficaz na identificação de candidíase e tricomoníase, apresentou baixa sensibilidade (0,0%; 50%) e valor preditivo positivo (0,0%; 3,6%) para as duas infecções e baixa especificidade para tricomoníase (46%). Mostrou-se satisfatório para vaginose bacteriana, com alta sensibilidade (100%), valor preditivo negativo (100%) e acurácia (74%). Conclui-se que o emprego do fluxograma precisa ser reavaliado, visto que não foi eficaz em identificar infecções importantes em gestantes. Os esforços para o desenvolvimento de testes eficazes devem ser contínuos, com intuito de prevenir a disseminação de infecções e reduzir tratamentos desnecessários.

Adsorção de ácidos húmicos em latossolo roxo natural e tratado com oxalato de amônio

A interação de substâncias húmicas com minerais no solo pode influir na dinâmica da decomposição da matéria orgânica e na sua estabilidade. A adsorção de dois ácidos húmicos em Latossolo Roxo natural (LR natural) e tratado com oxalato de amônio (LR tratado) foi efetuada, com vistas em investigar os mecanismos de adsorção e os principais grupos funcionais envolvidos, bem como relacionar a capacidade adsortiva de acordo com as características químicas e moleculares dos adsorbatos. Os ácidos húmicos extraídos com solução de NaOH 0,5 N de uma amostra de carvão (AHc) e de um solo Brunizém (AHs) foram caracterizados por análise elementar e espectroscopia de 13C-RMN. A parametrização dos dados experimentais das isotermas de adsorção foi do tipo y = A tanh Bx, e o modelo de Langmuir também foi aplicado. As amostras adsorvidas foram analisadas por espectroscopia no Infra-Vermelho por Reflectância Difusa com Transformada de Fourier (DRIFT). A adsorção dos ácidos húmicos no LR natural foi de natureza química, sendo evidenciado por DRIFT que a reação de troca de ligantes das carboxilas com a superfície dos minerais foi um mecanismo importante. O AHc, que apresentou caráter aromático mais elevado e maior teor de carboxilas na molécula, foi adsorvido em maior quantidade do que o AHs nos dois adsorventes, o que indica a possível participação de estruturas aromáticas na interação organomineral. No LR tratado, cuja área superficial específica foi superior (ASE = 140,9 m² g-1), a adsorção foi mais elevada do que no LR natural (ASE = 66,1 m² g-1). A maior ASE no LR tratado foi relacionada com o rompimento de microagregados no tratamento com oxalato de amônio que extraiu a porção cimentante dos óxidos de ferro que unia os minerais. A interação neste tipo de adsorvente, estimada segundo a equação y = A tanh Bx, foi mais forte do que na amostra natural, o que pode estar relacionado com a presença de sítios de adsorção hidrofóbica pela presença do oxalato na superfície, com a exposição de sítios mais reativos após tratamento e pH mais ácido. O modelo de Langmuir mostrou-se adequado para explicar a adsorção na amostra natural, enquanto, no LR tratado com oxalato de amônio, o ajuste não foi satisfatório. Em geral, a aplicação da equação y = A tanh Bx forneceu melhor ajuste (R² maior) do que a equação de Langmuir.