Examensarbetet handlar om kommunikation i matematikundervisningen. Idag domineras matematikundervisningen av enskilt arbete i läroboken, där elever sällan får utrymme att samtala och utbyta kunskaper med varandra. Det styrks vidare av granskningar som har genomförts av bland annat Matematikdelegationen (2004) och Skolinspektionen (2009).Syftet med studien är att undersöka matematiklärares tankar kring arbetet med kommunikation i matematikundervisningen. I undersökningen har en kvalitativ forskningsmetod tillämpats där datainsamlingen har skett med hjälp av kvalitativa intervjuer. Totalt har fyra verksamma matematiklärare i årskurs 4-6 intervjuats.Resultatet visar att samtliga respondenter delar samma uppfattning om vad kommunikation i matematikundervisningen innebär, vilket handlar dels om att redogöra och förmedla sina tankar men även att tolka andras. Samtliga lärare beskriver vidare EPA-metoden som ett sätt att bedriva en kommunikativ matematikundervisning. Därutöver menar de intervjuade lärarna att den största möjligheten vid arbetet med kommunikation i matematikundervisningen är att eleverna lär av varandra. Slutligen har det framkommit genom undersökningen att ett tillåtande klassrumsklimat är en god förutsättning för att bedriva en kommunikativ matematikundervisning.

Certains composants nutritionnels sont capables de moduler la réaction inflammatoire et la réponse immune. Ils pourraient être très utiles dans l’augmentation de la résistance de l’hôte aux maladies infectieuses, en particulier dans l’infection pulmonaire à P. aeruginosa qui est caractérisée par une réponse inflammatoire excessive et dont la sévérité est associée à une réponse immunitaire de type Th2. Le premier objectif de ce travail a été de tester l’effet anti-inflammatoire d’un régime enrichi acides gras polyinsaturés n-3 (EPA/DHA) au cours d’une infection pulmonaire aigue à P. aeruginosa sur des souris déficientes pour le gène cftr. Des résultats antérieurs suggérant que les souris femelles sont plus sensibles à l’infection que les souris mâles, les bénéfices de cette alimentation ont été analysés selon le sexe des souris. Le second objectif a été d’étudier l’effet des oligosaccharides acides dérivés de la pectine de Citrus (pAOS) au cours d’une infection pulmonaire chronique à P. aeruginosa. L’hypothèse testée était que les pAOS en favorisant le balancement de la réponse Th2 vers une réponse Th1 pourrait améliorer le pronostic de l’infection. Leur effet immunomodulateur a été évalué chez deux fonds génétiques murins différents : des souris BALB/c et C57BL/6 connues pour développer respectivement une réponse immune de type Th2 et Th1. Ces 3 études sont basées sur l’administration endo-trachéale d’une suspension de P. aeruginosa pour l’infection aigue ou de P. aeruginosa inclus dans des billes d’agar pour une infection chronique chez des souris nourries pendant 6 semaines (souris cftr-/-) et 5 semaines (BALB/c et C57BL/6) par une diète contrôle ou d’une diète spécifique. Les paramètres cliniques mesurés sont la survie et la clairance bactérienne pulmonaire, et les paramètres biologiques sont pour la réponse inflammatoire le dénombrement des polynucléaires, des macrophages et le dosage de cytokines pro- et anti-inflammatoires et pour la réponse immune le dosage des cytokines Th1 et Th2, l’expression de marqueurs de différentiation des lymphocytes Th1, Th2 et de polarisation des macrophages M1 et M2. Les souris BALB/c et C57BL/6 survivantes à une première infection ont été réinfectées et leur charge bactérienne pulmonaire a été mesurée. / Some nutritional components are able to modulate the inflammatory response and the immune response. They could be very useful in increasing the host resistance to infectious diseases, particularly in the P. aeruginosa pulmonary infection which is characterized by an excessive inflammatory response and the severity of which is associated with a Th2 type immune response. The first objective of this study was to test the anti-inflammatory effect of a diet enriched in n-3 polyunsaturated fatty acids (EPA/DHA) during an acute pulmonary infection with P. aeruginosa in mice deficient for the cftr gene. Because previous results suggested that female mice are more susceptible to infection than male mice, the benefits of this diet were analyzed according to the mice gender. The second objective was to study the effect of acidic oligosaccharides derived from citrus pectin (pAOS) during a chronic lung infection with P. aeruginosa. The hypothesis was that pAOS by promoting the balancing of the Th2 response towards a Th1 response could improve the prognosis of the infection. Their immunomodulatory effect was evaluated in two different murine genetic backgrounds: BALB/c and C57BL/6, known to develop respectively a Th2 and a Th1 immune response. These three studies are based on the endotracheal administration of a suspension of P. aeruginosa for the acute infection or P. aeruginosa embedded in agar beads for the chronic infection in mice fed a control diet or a specific diet for 6 weeks (cftr-/- mice) or 5 weeks (BALB/c and C57BL/6). The clinical parameters measured were survival and pulmonary bacterial clearance. Biological parameters for the inflammatory response were the polymorphonuclear cells and macrophages counting and pro- and anti-inflammatory cytokines assay in the bronchoalveolar lavage, and for the immune response the Th1 and Th2 cytokines assay, the expression of differentiation markers of Th1 and Th2 cells and M1 and M2 macrophages. BALB/c and C57BL/6 surviving at the first infection were reinfected and the pulmonary bacterial load was measured.

Asbestos sampling and monitoring data, starting from 2003, located in a large federal facility’s Asbestos Air Database Management (AADM) repository will be queried and analyzed on airborne asbestos fiber concentrations generated from abatement activities of asbestos-containing materials (ACM) and asbestos-containing building materials (ACBM). Historically, concerns expressed by personnel outside of the containment areas, whether adjacent to or quite a distance from the asbestos abatement activities present operational challenges for the project manager, potential angst and uneasiness to personnel residing next to the abatement activity as well as programmatic concerns to the building/facility managers. The concerned individuals working outside the abatement enclosure, in an unrelated activity to the abatement often believe there is a high probability for personal exposures of asbestos fibers based on their proximity to the abatement activities. Perceptions regarding containment performance, the uncertainty surrounding the long latency period between asbestos fiber exposure and onset of disease, and the lack of understanding about containment efficacy are just some of the elements that can generate worry. Using statistical analysis tools, such as regression analysis, relationships between one or more predictor variables relative to a response variable were investigated. This research reviewed and compared airborne asbestos fiber sample data relative to the specific activities, whether abatement or other, that were performed. In an effort to establish a holistic awareness to the reader as to why individuals are concerned about being located near asbestos abatement activities, the history of asbestos regulation and epidemiology is also discussed. The dataset contained 5534 sampling records made up of 3738 area samples (1426 outside containment structure and 2312 inside containment structure) and 1796 personal samples. Analysis identified that 1779 (>99%) out of the 1796 total personal exposure samples in the dataset indicated the asbestos workers were appropriately protected from overexposures. Only seventeen (<1%) of the 1796 total personal exposure samples exceeded the respective Occupational Exposure Limits (OELs): • Fifteen of the 17 exceeded the 8-hr TWA, 0.1 f/cc OEL. These exceedances were positively correlated with work tasks identifying that no respirators were required due to a Negative Exposure Assessment (NEA). • Two of the 17 exceeded the Assigned Protection Factor for the Half Face APR (10x the OEL protection) adjusted 8-hr TWA OEL, 1 f/cc. • There were no OEL exceedances identified for any 30-min Excursion personal sampling events. The focus for this assessment was to determine the efficacy of the asbestos abatement process and increased health risks to personnel. The findings suggest there is performance variability in the containment structures; however, the abatement process was effective and protective of the non-asbestos personnel outside of the abatement work area. It can also be concluded that the abatement process of containment structures, negative air, work methods (e.g. wet methods) and Personal Protective Equipment (PPE) have provided a protective environment for both workers and non-asbestos personnel outside of the containment structures.

O presente estudo foi conduzido com o objetivo de avaliar o efeito da adição de suplemento contendo microalgas ricas em ácido docosahexaenoico (DHA) no período periparto sobre o processo de involução uterina de éguas. Foram utilizadas 18 éguas sem raça definida, com 410 &#177; 39,5 kg (média &#177; desvio padrão) de peso corporal, 7,83 &#177; 2,01 anos de idade e escore de condição corporal 5,39 &#177; 0,61. Noventa dias antes da data de parto prevista, os animais foram aleatoriamente alocados para receber um dos tratamentos experimentais: CONT: sem a adição de suplemento rico em microalgas; e ALG: com a adição de 0,06 g/kg de peso corporal/dia de microalga (All-G Rich&reg;, Alltech, Nicholasville, KY). As éguas foram mantidas em pastagem de Cynodon e receberam 1 kg/dia de concentrado no pré-parto e 2 kg/ dia após o parto, divididos em dois fornecimentos diários. As éguas foram avaliadas por palpação retal, ultrassonografia no modo B e Doppler, aos 3, 7, 11, 15 após o parto e 4 e 7 dias após a primeira ovulação pós parto. Os dados foram divididos em avaliações pós parto (3, 7, 11 e 15 dias) e pós ovulação (4 e 7 dias) e foram avaliados como medidas repetidas no tempo, utilizando o PROC MIXED do SAS (versão 9.3). Independentemente (P &ge; 0,508) do tempo de avaliação, a adição de suplemento rico em microalgas não afetou (P &ge; 0,265) o diâmetro do endométrio. Em relação aos animais do grupo CONT, os animais do grupo ALG apresentaram menor (P = 0,042) diâmetro do mesométrio do corno gestante após o parto e tenderam (P = 0,093) a apresentar menor diâmetro no corno não gestante. Os diâmetros do endométrio e mesométrio foram afetadas (P &lt; 0,001) pelo tempo de avaliação pós parto. De maneira geral, com a passagem do tempo, os diâmetros foram reduzidos. Nem a adição de microalgas (P &ge; 0,185), nem o tempo de avaliação (P &ge; 0,164) afetaram a vascularização do endométrio e do mesométrio. A suplementação com microalgas aumentou (P = 0,004) a ecogenicidade uterina pós parto, sem afetar (P &ge; 0,392) a presença de fluido uterino, o diâmetro do folículo dominante, os intervalo entre o parto e a primeira ovulação, assim como o escore de condição corporal dos animais. Independentemente (P &ge; 0,523) do tratamento, com o passar do tempo, houve redução (P &le; 0,05) da quantidade de fluido uterino e aumento (P &le; 0,05) do diâmetro do folículo dominante. A suplementação com microalgas ricas em DHA na dieta de éguas, apesar de reduzir o diâmetro do mesométrio e aumentar a ecogenicidade uterina, não afeta a recuperação uterina pós-parto, nem reduz o intervalo entre o parto e a primeira ovulação. / The present study aimed to evaluate the effect of dietary supplementation of microalgae rich in docosahexaenoic acid (DHA) to periparturient mares on uterine involution process. Eighteen mares with 410 &#177; ± 39.5 kg (mean ± standard deviation) of body weight, 7.83 &#177; 2.01 years of age and body condition score 5.39 &#177; 0.61 were used. Ninety days before the expected calving date, animals were randomly allocated to receive one of the experimental treatments: CONT: without supplemental microalgae; and ALG: algae, with the addition of 0.06 g/kg body weight/d of microalgae (All-G Rich&reg;, Alltech, Nicholasville, KY). Animals were maintained on Cynodon pasture and received 1 kg /d of concentrate supplement in prepartum and 2 kg/d in post partum, supplied twice daily. Mares were evaluated by rectal palpation, B mode and Doppler ultrasonography at 3, 7, 11, and 15 days postpartum and 4 and 7 days post ovulation. The data were divided into postpartum (3, 7, 11 and 15 days) and post ovulation (4 and 7 days postpartum) evaluations and were evaluated as time-repeated measures using SAS MIXED PROC (version 9.3). The addition of ALG had no effect (P &ge; 0.508) on endometrial diameter regardless evaluation time (P &ge; 0.265). In relation to CONT-treated animals, the animals of the ALG group had lower (P = 0.042) mesometrial diameter of the pregnant horn and tended (P = 0.093) to show decreased diameter of non-pregnant horn. Endometrial and mesometrial diameters were affected (P &lt;0.001) by the time of postpartum evaluation. In general, with passage of time, the diameters were reduced. Neither the addition of microalgae (P &ge; 0.185) nor the time of evaluation (P &ge; 0.164) affected endometrium and mesometrium vascularization. Microalgae supplementation increased (P = 0.004) postpartum uterine echogenicity without affecting (P &ge; 0.392) the presence of uterine fluid, the diameter of dominant follicle, interval between partum and fist ovulation, and animal body score condition. Over time, there was decrease (P &le; 0.05) in the amount of uterine fluid and increase (P &le; 0.05) in dominant follicle. Dietary supplementation of DHA-rich microalgae in periparturients mares, although reducing mesometrium diameter and increasing uterine echogenicity, shows no effect on postpartum uterine recovery and interval between partum and first ovulation.

The topic dealt by this study is about protection of GIs, and the problem attempted is what should be the position of the EAC regarding the protection of GIs in the final EPA negotiations with the EU? In addressing this problem, the paper hypothesised that, there are abundant potential GIs in the EAC and their protection can result to profound positive economic contribution to the region. Hence, EAC should opt for the protection of GIs in the final EPA text with the EU. Moreover, most potential GIs found in the EAC are agro-based products of which their production costs are less than EU’s GIs, because of comparative advantage in agricultural production. It follows therefore that, in addressing the said problem the paper runs as follows. Chapter one addresses historical overview of the ACP-EU relations that resulted to the current EPA’s negotiations, objectives and principles of EPA, and lastly the current status of EAC-EPA negotiations. Whereas in chapter three meaning of the term GI, Legal frameworks used to protect GIs are comprehensively examined. Also in this chapter the feasibility of EAC legal framework for protecting GIs is also explored. Chapter four addresses the economic rationale and associated benefits of protecting GIs, and the requisite conditions needed for a product to qualify GI status. Whilst chapter five addresses potential GIs found in the EAC partner states, policies and legal frameworks available to administer such potential GIs. Chapter six covers general conclusion for various findings observed by the study and provides recommendations as to which position should EAC opt, reasons for the same and also addresses possible areas for future research. Conclusively, the paper after intense observations, recommends the EAC to opt for inclusion of the GIs in the final EPA text. The reason being that, there are several economic, social and ecological benefits accrued from protecting GIs. However in the course of implementations,there are certain costs associated with changes in the newly introduced institutions, policy and legal structural reforms etc. Due to these expenses the paper recommends proper utilisation of the existing institutions to reduce administrative costs etc / Dissertation (LLM)--University of Pretoria, 2010. / Centre for Human Rights / unrestricted

La retina es el tejido neural que tapiza la parte posterior del ojo. En los vertebrados está constituida por cinco clases de neuronas: los fotorreceptores (conos y bastones), las amacrinas, las horizontales, las ganglionares, y las bipolares. Debido a su relativa simplicidad, accesibilidad y a que los distintos tipos celulares están organizados formando un tejido altamente estructurado, la retina ha sido ampliamente utilizada como tejido modelo de estudio del sistema nervioso central, y es la estructura neural más estudiada. Las neuronas de retina debido a su constante exposición a la luz, su alta tasa metabólica y el alto contenido de ácidos grasos en sus membranas son muy sensibles a sufrir daño oxidativo. Este daño es el responsable de disparar procesos de apoptosis en este tejido. Muchas enfermedades neurodegenerativas de la retina involucran la muerte por apoptosis de las neuronales retinales, y tienen en común que el daño oxidativo es un desencadenante. Este estrés activa vías que involucran a las mitocondrias y conduce a la apoptosis. El conocimiento de los mecanismos por los cuales induce dicha activación es fundamental en el desarrollo de futuras estrategias terapéuticas. Trabajos previos de nuestro laboratorio demuestran que la carencia de factores tróficos durante el desarrollo neuronal in vitro y el estrés oxidativo inducido por PQ inducen la muerte por apoptosis de las neuronas fotorreceptoras. El ácido docosahexaenoico (DHA, 22:6 n-3) es un ácido graso poliinsaturado esencial de la familia de los omega 3, sintetizado a partir del ácido ɑ-linolénico (18:3 n-3) y se encuentra altamente concentrado en las células del sistema nervioso, principalmente en las membranas sinápticas y en los fotorreceptores. El DHA en el sistema nervioso desarrolla múltiples funciones, juega un papel importante en el proceso de fototransducción, en la formación de la memoria, es neuroprotector y puede regular procesos antiinflamatorios. Tradicionalmente al DHA en la retina se lo relaciona con un importante rol estructural, el de favorecer los cambios de conformación inducidos por la luz en la rodopsina, y es indispensable para el adecuado desarrollo de la visión. En nuestro laboratorio, se ha establecido un rol completamente nuevo para el DHA, el de ser un factor de supervivencia previniendo la apoptosis de los fotorreceptores por ausencia de factores tróficos durante su desarrollo in vitro y previniendo la apoptosis inducida por el oxidante Paraquat (PQ). Además hemos establecido que promueve la diferenciación de los fotorreceptores de retina de rata en cultivo. Hemos demostrado que el PQ dispara la apoptosis de las neuronas de retina en cultivo; el aumento de la apoptosis se encuentra en estrecha relación con la pérdida de integridad mitocondrial en las neuronas y se observó que los fotorreceptores son más sensibles que las neuronas amacrinas a la apoptosis inducida por PQ. El H2O2 es un agente oxidante que, a diferencia del PQ, es en sí mismo una especie oxígeno reactiva (ROS) y un mediador fisiológico del daño oxidativo en retina. En nuestro laboratorio también se demostró que el H2O2 induce un aumento de la muerte celular por apoptosis de los fotorreceptores. Es por eso que decidimos investigar en este trabajo de tesis si el DHA también puede prevenir la apoptosis disparada por H2O2, que induce la muerte de las células de retina luego de agotar los sistemas de defensa antioxidante. Para ello suplementamos cultivos neuronales de retina con o sin DHA e indujimos daño oxidativo con H2O2. Evaluamos viabilidad celular con ioduro de propidio y observamos que, al tratar a los cultivos con H2O2, en ausencia de DHA, disminuye la viabilidad celular respecto a los controles. Si previo al tratamiento con H2O2 los cultivos fueron suplementados con DHA el porcentaje de células muertas descendió a niveles comparables con los de los controles. Para determinar el efecto del DHA frente a la apoptosis inducida por H2O2 realizamos el ensayo de TUNEL y vimos un aumento de los fotorreceptores TUNEL+ en los cultivos tratados con H2O2, y una disminución de los mismos en los cultivos preincubados con DHA. Cuantificamos el porcentaje de fotorreceptores con núcleos picnóticos o fragmentados, teñidos con DAPI, para evaluar apoptosis y observamos que el H2O2 provocó un aumento de la apoptosis de los fotorreceptores respecto a los cultivos controles y que el DHA agregado previo al tratamiento con H2O2 previno la apoptosis de los fotorreceptores. Estos resultados, junto con el hecho de que el DHA protege a los fotorreceptores del daño oxidativo inducido por PQ, nos permiten concluir que el DHA es un eficaz protector de las neuronas fotorreceptoras de retina expuestas a distintos tipos de agentes oxidantes. Resultados previos de nuestro laboratorio establecieron que el DHA en cultivos neuronales de retina se incorpora a la membrana de las células, aumenta su concentración en las mismas y tiene la capacidad de activar la vía de la ERK/MAPK y regular la relación de proteínas pro y antiapoptóticas para promover la supervivencia de los fotorreceptores frente al daño oxidativo (Ger)man et al., 2006a;Rotstein et al., 2003. En este trabajo de tesis nos propusimos investigar si el DHA, además de activar las vías de supervivencia citadas, también podría estar ejerciendo su efecto protector actuando como antioxidante. Para determinar si el DHA estaría actuando como un agente antioxidante utilizamos la sonda DCFDA para medir la formación de (ROS en los cultivos y así tener una medición aproximada del daño oxidativo en los cultivos (Halliwell and Whiteman, 2004;Lu et al., 2006). Determinamos el porcentaje de fluorescencia de la sonda DCFDA oxidada respecto al control. Observamos que el porcentaje de fluorescencia aumentó al tratar los cultivos con H2O2, indicando un aumento en la formación de ROS. Observamos también que el DHA disminuyó la formación de ROS disparada por H2O2 en los cultivos neuronales de retina de rata. Para investigar si el DHA estimula enzimas del sistema de defensa antioxidante, determinamos la actividad de la GPx, que participa de la reducción de hidroperóxidos al catalizar la oxidación del Glutatión. Vimos que en cultivos suplementados con DHA previo a inducir daño oxidativo, la actividad de la enzima fue mayor que en los cultivos controles, por lo que el DHA estaría estimulando la actividad de esta enzima. Decidimos medir los niveles de sustancias reactivas con el ácido barbitúrico (TBARS) como indicador de peroxidación lipídica en los cultivos neuronales de retina tratados con H2O2. Observamos que el H2O2 aumentó los niveles de TBARS y por lo tanto la peroxidación lipídica en los cultivos neuronales de retina. Además al suplementar con DHA, independientemente de si se indujo o no estrés oxidativo con H2O2, aumentaron los niveles de TBARS respecto a cultivos sin DHA. De estos resultados se desprende que el DHA, a pesar de aumentar la peroxidación lipídica en los cultivos neuronales, promueve la supervivencia de los fotorreceptores al activar enzimas de defensa antioxidante, como la GPx, y disminuir la formación de ROS. La síntesis de DHA a partir de EPA (Acido eicosapentaenoico, 20:5 n-3) requiere de dos elongaciones que forman TPA (ácido tetracosapentaenoico, 24:5 n-3), que es posteriormente desaturado por la Δ6-desaturasa produciendo THA (ácido tetracosahexaenoico, 24:6 n-3). Finalmente este, por acción de una β-oxidasa peroxisomal, da origen al DHA. Este proceso biosintético requiere de la incorporación de los precursores desde la dieta y es principalmente llevado a cabo en el hígado. El DHA así sintetizado es luego distribuido a distintos tejidos por el sistema circulatorio. Si bien la mayor cantidad de DHA del sistema nervioso proviene de la síntesis hepática y su transporte unido a lipoproteínas de la sangre también ocurre la síntesis in situ, aunque en menor medida. Las enzimas necesarias para la síntesis de DHA están presentes en el ojo, siendo el epitelio pigmentario el sitio donde es más efectivo este proceso de síntesis. Está comprobado que este camino biosintético puede llevarse a cabo en células gliales, pero no se ha demostrado la síntesis del DHA en neuronas. En este camino metabólico el ácido eicosapentaenoico (EPA, 20:5n-3) es un intermediario, y al igual que el DHA, el EPA ha demostrado tener efectos importantes en el cerebro y retina. En retinas de rata alimentadas con dietas ricas en ácidos grasos de la serie n-3 aumenta la relación EPA/AA (EPA/Acido Araquidónico) en los segmentos externos de los fotorreceptores y disminuyen los daños a nivel de dichos segmentos externos cuando se somete a estas ratas a un daño agudo inducido por luz. Por otro lado el aumento de los niveles de EPA plasmático en pacientes humanos sanos se relaciona directamente con el aumento de la densidad del pigmento macular que regula procesos inflamatorios y previene el daño oxidativo previniendo el avance de la degeneración macular. De todos modos, aun se desconocen los mecanismos celulares y moleculares por medio de los cuales el EPA actúa como un agente neuroprotector. Como el EPA ha demostrado tener efectos muy similares a los que se observan con el DHA en diferentes modelos animales y celulares, en esta tesis investigamos si al igual que ocurre con el DHA, la suplementación de cultivos neuronales de retina con EPA es capaz de prevenir la apoptosis inducida por daño oxidativo en los fotorreceptores y promover su diferenciación. También analizamos si el EPA en neuronas de retina aisladas puede actuar como precursor metabólico del DHA, promoviendo su síntesis y si esta síntesis es indispensable para que el EPA actúe como agente neuroprotector y promotor de la diferenciación de los fotorreceptores. Para evaluar si el EPA es capaz de proteger a los FR de la apoptosis inducida por PQ, suplementamos los cultivos con EPA en concentraciones crecientes (2, 3, y 6 μM) y los tratamos con PQ. Evaluamos luego viabilidad celular, con IP y apoptosis por el estudio de la morfología nuclear con DAPI. Tanto en los cultivos controles, como en los suplementados con las distintas concentraciones de EPA se observaron porcentajes bajos de muerte celular y de fotorreceptores apoptóticos. La suplementación con EPA, previa al tratamiento con PQ previno el aumento en la mortalidad celular y en la apoptosis inducida por PQ de los fotorreceptores en una forma dosis dependiente. Determinamos que la concentración 3 μM de EPA era la más efectiva. Confirmamos el efecto protector del EPA 3 μM frente a la apoptosis inducida por PQ en los fotorreceptores utilizando el ensayo de TUNEL. El PQ indujo un aumento de los FR TUNEL + y la adición de EPA previa al tratamiento con PQ disminuyó el número de fotorreceptores TUNEL + a niveles comparables con los de los cultivos controles. Por lo tanto, el EPA, al igual que el DHA actúa como un agente protector frente a la muerte inducida por PQ en los fotorreceptores en cultivos. Esto nos llevó a plantearnos si otros ácidos grasos también podrían actuar de esta manera. Para contestarlo decidimos investigar si los ácidos araquidónico (20:4 n-6, AA), palmítico (16:0, PA) y oleico (18:1 n-9, OA) presentaban efectos antiapoptóticos frente al daño oxidativo inducido con PQ. A diferencia del EPA, ninguno de estos ácidos al ser agregados a los cultivos, evitó los procesos de muerte celular y apoptosis de fotorreceptores desencadenados por el tratamiento con PQ. Podemos afirmar entonces que sólo el EPA y el DHA disminuyen la apoptosis de los fotorreceptores inducida por PQ. Quisimos evaluar si el EPA también podría tener efecto protector frente a otro oxidante como el H2O2. El tratamiento con H2O2 provocó un marcado aumento de la apoptosis, aumentando significativamente el número de fotorreceptores con núcleos picnóticos y mitocondrias despolarizadas. La suplementación de los cultivos con EPA previo al tratamiento con H2O2 previno el aumento del número de fotorreceptores con núcleos picnóticos o fragmentados y mantuvo intacto el potencial de membrana mitocondrial en la mayoría de los fotorreceptores, al igual que en los controles. Estos resultados demuestran el rol protector del EPA frente a la apoptosis inducida por distintos tipo de daño oxidativo inducido a los fotorreceptores en cultivo. Resultados anteriores de nuestro laboratorio establecieron que in vitro, debido a la carencia de factores tróficos, la diferenciación de los fotorreceptores está restringida y en nuestros cultivos, los fotorreceptores, presentan morfología característica de fotorreceptores no diferenciados. El DHA estimula la diferenciación de los fotorreceptores. En este trabajo quisimos ver si el EPA jugaba algún rol en la diferenciación de los fotorreceptores en cultivo. Establecimos que la adición de EPA provocó un aumento de la expresión de opsina en los fotorreceptores y promovió el crecimiento de procesos apicales, rudimentos de los segmentos externos. Por lo que el EPA estimula la diferenciación de los fotorreceptores durante el desarrollo en cultivo. También nos propusimos evaluar si el EPA es capaz de modificar la composición de ácidos grasos de los fosfolípidos de la retina neural. El análisis por GLC de la composición de ácidos grasos de los cultivos neuronales reveló valores de EPA muy bajos en los cultivos controles. Sorprendentemente, no existió una acumulación significativa de este ácido graso en los fosfolípidos luego de la incubación con EPA pero que sí se duplicaron los niveles de DHA. Esto nos llevó a suponer que los fotorreceptores y/o neuronas amacrinas en nuestros cultivos eran capaces de elongar y desaturar al EPA para producir DHA. Para que este proceso metabólico pueda llevarse a cabo es clave la presencia de la enzima Δ6 desaturasa, responsable de la transformación del TPA al THA. Investigamos por técnicas inmunocitoquimicas y western blot si esta enzima se expresa en los cultivos neuronales de retina. El western blot reveló la expresión de la enzima en los cultivos neuronales de retina. La citoquímica mostró que la enzima estaba presente tanto en el citoplasma como en los núcleos de los fotorreceptores y las células amacrinas. Estos resultados demuestran, por primera vez, que las neuronas de retina son capaces de sintetizar DHA a partir de EPA como precursor. El hecho de que el EPA en nuestros cultivos esté promoviendo la síntesis de DHA sumado a que los efectos que presenta son los mismos que se vieron con anterioridad por parte del DHA, nos llevó a plantearnos la hipótesis de que este ácido graso no estuviera actuando por sí mismo, sino como consecuencia de su metabolización a DHA. Para respondernos este interrogante, preincubamos a los cultivos con CP24879 (CP), un inhibidor de las Δ5 y Δ6 desaturasas, antes de suplementarlos con EPA. Como era de esperar, la presencia del inhibidor previno el aumento de los niveles de DHA y condujo a un aumento del contenido de DPA en los cultivos suplementados con EPA. Evaluamos el efecto del agregado de CP sobre la protección del EPA frente al tratamiento con H2O2. El agregado de CP bloqueó por completo el efecto protector del EPA frente a la apoptosis inducida por H2O2, y el porcentaje de fotorreceptores apoptóticos fue el mismo que el que observamos en los cultivos tratados con H2O2 sin EPA. También analizamos si la síntesis de DHA era necesaria para promover la diferenciación de los fotorreceptores. Para ello, investigamos si la incubación con CP afectaba al aumento en la expresión de opsina que provoca el EPA en los cultivos neuronales. El EPA provocó un aumento en la cantidad de fotorreceptores que expresaron opsina, pero la incubación previa con CP bloqueó este efecto y la cantidad de fotorreceptores opsina + en estos cultivos fue comparable con la que observamos en los cultivos controles. Por lo tanto estos resultados indican que la adición de EPA a los cultivos neuronales de retina previene la apoptosis de los fotorreceptores expuestos a condiciones de estrés oxidativo y estimula el avance de la diferenciación de las neuronas fotorreceptoras. También demuestran que al inhibir la actividad de la Δ6 desaturasa, enzima que cataliza la reacción requerida para la síntesis de DHA a partir de EPA, se bloquean los efectos del EPA sobre los fotorreceptores. Esto implica que no es el EPA en sí mismo el que previene la apoptosis y favorece la diferenciación de los FR en cultivo, sino que es el DHA sintetizado a partir del EPA En resumen, las conclusiones más destacadas de este trabajo de tesis son las siguientes:  El DHA previene la muerte por apoptosis inducida por H2O2 de los fotorreceptores en cultivo.  El DHA frena la formación de ROS inducida por H2O2  El agregado de DHA aumenta los niveles de peroxidación lipídica en los cultivos neuronales de retina.  El DHA activa enzimas que participan de los mecanismos de defensas antioxidantes para prevenir la formación de ROS que estimula el H2O2.  El agregado de EPA, y no de otros ácidos grasos, previene la apoptosis inducida por PQ y H2O2, efecto que son comparables al observados al suplementar los cultivos con DHA.  El agregado de EPA promueve la diferenciación de los fotorreceptores durante el desarrollo in vitro, aumentando los niveles de expresión de opsina y la formación de procesos apicales.  Los fotorreceptores de rata en cultivo expresan Δ6 desaturasa, esencial para la síntesis de DHA.  Las neuronas de retina de rata en cultivo son capaces de sintetizar DHA a partir de EPA.  El EPA debe ser metabolizado a DHA para proteger a los fotorreceptores de la apoptosis inducida por estrés oxidativo y para promover la diferenciación de los mismos. / The neural retina is the tissue in the back of the eye. In vertebrates it consists of five types of neurons: photoreceptor (rods and cones), amacrine, horizontal, ganglion, and bipolar neurons. The retina is the most studied neural structure because its different cell types are arranged to form a highly structured tissue, and due to its relative simplicity, and its accessibility, and has been widely used as a model for studying the central nervous system. Due to their constant exposure to light, high metabolic rate and high content of fatty acids in their membranes retinal neurons are very sensitive to oxidative damage. This damage is responsible for triggering apoptosis in this tissue. Many neurodegenerative retinal diseases have in common the apoptotic death of retinal neuronal and that oxidative damage acts as a trigger of this death. This stress-activated pathway involving mitochondria leads to apoptosis. Knowledge of the mechanisms by which this activation is induced is critical in the development of future therapeutical strategies. Previous work from our laboratory has shown that the absence of trophic factors during neuronal development in vitro and induction of oxidative stress by paraquat (PQ) treatment leads to the apoptotic death of photoreceptor neurons. Docosahexaenoic acid (DHA, 22:6-3) is a polyunsaturated fatty acid of the omega-3 family, synthesized from linolenic acid (18:3 n-3) and is highly concentrated in the cells of the nervous system, especially in synaptic membranes and in photoreceptors. DHA plays multiple functions in the nervous system; it has an important role in the phototransduction process, in the formation of memory, it is neuroprotective and it can regulate inflammatory processes. Traditionally, DHA in the retina has been related to an important structural role, favoring the conformational changes induced by light in rhodopsin, and it is known to be essential for proper development of vision. In our lab, we have established a completely new role for DHA, that of being a survival factor preventing apoptosis of photoreceptors in the absence of trophic factors during in vitro development. We have also established that it promotes differentiation of rat retinal photoreceptors. We have also shown that the oxidant paraquat (PQ) triggers apoptosis of retina neurons in culture, the increase in apoptosis being closely related to the loss of mitochondrial integrity. We demonstrated that photoreceptors are more sensitive than amacrine neurons to PQ-induced apoptosis. H2O2 is an oxidizing agent that, unlike PQ, is in itself a ROS (Reactive oxygen species) and a physiological mediator of oxidative damage in the retina. In our laboratory we demonstrated that H2O2 induces apoptosis of photoreceptors. In this Thesis we investigated if DHA can also prevent H2O2-induced apoptosis after exhausting the retinal antioxidant defense systems. To do this we supplemented retina neuronal cultures with or without DHA and we induced oxidative stress with H2O2. We assessed cell viability with propidium iodide and observed that treatment of cultures with H2O2 in the absence of DHA decreased cell viability relative to controls. If cultures were supplemented with DHA previous to H2O2 treatment, the percentage of dead cells decreased to levels comparable to those found in controls. To determine the efficacy of DHA to prevent apoptosis induced by H2O2 we evaluated apoptosis with the TUNEL assay and established that H2O2 treatment increased TUNEL + photoreceptors, while they were decreased in cultures preincubated with DHA. To evaluate apoptosis we quantified the percentage of photoreceptors showing fragmented or pyknotic nuclei by staining nuclei with DAPI and observed that H2O2 treatment increased apoptosis of photoreceptor compared to controls and pretreatment with DHA prevented H2O2-induced apoptosis of photoreceptors. These results, together with the fact that DHA protects photoreceptors from oxidative damage induced by PQ, allow us to conclude that DHA is an effective protector of retinal neurons exposed to various types of oxidizing agents. Previous results from our laboratory have established that DHA added to retinal neuronal cultures is incorporated into cell membranes, increasing its levels in neuronal lipids, activating the ERK / MAPK pathway and regulating the ratio of pro to anti-apoptotic proteins, thus promoting photoreceptor survival upon oxidative damage. In this Thesis we investigated whether DHA could also be exerting its protective effect by acting as an antioxidant. To evaluate this we used the DCFDA probe to measure the formation of ROS in culture and get a rough measure of oxidative damage. We determined the percentage of the DCFDA fluorescence probe oxidized over control and established that the percentage of fluorescence increased by treating the cultures with H2O2, indicating an increase in ROS formation. We also showed that DHA decreased ROS formation triggered by H2O2 in neuronal cultures of rat retina. To investigate whether DHA stimulates enzymes from the antioxidant defense system, we determined the activity of glutathione peroxidase (GPx), which participates in the reduction of hydroperoxides by catalyzing the oxidation of GSH. We established that in cultures supplemented with DHA previous to the induction of oxidative damage the enzimatic activity was higher than in control cultures, suggesting DHA stimulates the activity of this enzyme . We measured the levels of TBARS as an indicator of lipid peroxidation in neuronal cultures treated with H2O2. We observed that H2O2 increased TBARS levels and therefore lipid peroxidation in retinal neuronal cultures. DHA supplementation caused an increase in TBARS levels compared to cultures without DHA, both in the presence or the absence of oxidative damage. From these results it is apparent that DHA, in spite of the increase it triggers in lipid peroxidation in neuronal cultures, promotes photoreceptor survival by activating antioxidant defense enzymes such as GPx, and reducing the formation of ROS. DHA synthesis from EPA (eicosapentaenoic acid, 20::5 n-3) requires two elongations that form TPA (tetracosapentaenoic acid, 24:5 n-3), which is subsequently desaturated by the Δ6-desaturase producing THA (24:6 n-3, tetracosahexaenoic acid). Finally THA is decarboxylated to DHA by a peroxisomal β-oxidase. This biosynthetic pathway requires the provision of precursors in the diet and is mainly carried out in the liver. DHA is then distributed to various tissues through the circulatory system. While most of the DHA in the nervous system comes from the hepatic synthesis and lipoprotein transport of blood, in situ synthesis also occurs though to a lesser extent. The enzymes necessary for the synthesis of DHA are present in the eye and its synthesis is more effective in retinal pigment epithelium than in the retina. It has been shown that this biosynthetic pathway can be carried out in glial cells, but it is still unknown whether this synthesis occurs in neurons. In this metabolic pathway EPA is an intermediate, and like DHA, it has been shown to have significant effects on the brain and retina. In rats fed diets rich in fatty acids of the n- 3 series, the EPA/AA (EPA /arachidonic acid) ratio increases in the outer segments of photoreceptors and the damage to these outer segments is reduced when rats are subjected to acute light-induced damage. Moreover, increased levels of EPA in plasma of healthy human patients are directly related to increased macular pigment density, which regulates inflammatory response, and prevents oxidative damage and the progression of macular degeneration. However, the molecular and cellular mechanisms by which EPA acts as a neuroprotective agent are still unknown. As EPA has demonstrated effects very similar to those observed with DHA in different animal and cellular models, here we investigated whether EPA was able to prevent apoptosis of photoreceptors induced by oxidative damage and promote their differentiation. We also investigated if EPA acted as a metabolic precursor of DHA in retina neurons, promoting its synthesis and if this synthesis was essential for EPA effects in photoreceptors. To assess whether EPA is able to protect photoreceptors from PQ-induced apoptosis, we supplemented cultures with increasing concentrations of EPA (2, 3, and 6 μM) and treated them with PQ. Then we evaluated cell viability with PI, and studied apoptosis by DAPI staining. Low percentages of cell death and apoptotic photoreceptors were observed both in control cultures and in those supplemented with different concentrations of EPA. Supplementation with EPA prevented the increased in cell death and apoptosis induced by PQ in a dose dependent manner. We determined that the 3 uM EPA concentration is the most effective. We confirmed the protective effect of 3 μM EPA from apoptosis induced by PQ in photoreceptors by TUNEL assay. PQ induced an increase in TUNEL + photoreceptors and EPA addition prior to treatment with PQ decreased the number of TUNEL + photoreceptors to levels comparable with control cultures. Therefore, the EPA, like DHA acts as a protective agent against PQ-induced death in photoreceptors in culture. This led us to ask whether other fatty acids might also act in this way. To answer this we decided to investigate whether arachidonic acid (20:4 n-6, AA), palmitic (16:0 PA) and oleic (18:1 n- 9) acids had antiapoptotic effects against oxidative damage induced by PQ. Unlike EPA or DHA, none of these fatty acids when added to the cultures prevented cell death and photoreceptor apoptosis triggered by PQ. We can propose that only EPA and DHA decreased photoreceptor apoptosis induced by PQ. We wanted to assess whether EPA was also protective against other oxidants such as H2O2.Treatment with H2O2 caused a marked increase in apoptosis, significantly increasing the number of photoreceptors with pyknotic nuclei and depolarized mitochondria. Supplementation of the cultures with EPA prior to treatment with H2O2 prevented the increase in the amount of photoreceptors with fragmented or pyknotic nuclei and retained mitochondrial membrane potential in most photoreceptors, with values similar to control cultures. These results demonstrate the protective role of EPA from apoptosis induced by different types of induced oxidative damage to photoreceptors in culture. Previous results from our laboratory have established that in vitro, due to lack of trophic factors, differentiation of photoreceptors is restricted and in our cultures, photoreceptors exhibit an undifferentiated morphology. DHA stimulates photoreceptors differentiation. In this study we investigated whether EPA played a role in the differentiation of photoreceptors in culture. We established that EPA addition promoted an increase in opsin expression in photoreceptors and promoted the development of apical processes. EPA therefore stimulates the differentiation of photoreceptors during development in culture. We also set out to assess whether EPA was able to modify the fatty acid composition of phospholipids of cultured neurons. GLC analysis of fatty acid composition of the cultured neurons revealed very low levels of EPA in control cultures. Surprisingly, there was no significant accumulation of this fatty acid in phospholipids after incubation with EPA but DHA levels were doubled. This led us to presume that photoreceptors or amacrine neurons in our cultures were able to elongate and desaturate EPA to produce DHA. Δ6-desaturase enzyme is a key enzyme in this process. It is responsible for the transformation of TPA to THA. We investigated by Western blot and immunocytochemical techniques if this enzyme was expressed in the retinal neuronal cultures. Western blot analysis revealed the expression of the enzyme in retinal neurons. Cytochemistry showed that the enzyme was present in both the cytoplasm and nuclei of photoreceptors and amacrine neurons. These results demonstrate, for the first time, that retinal neurons are able to synthesize DHA using EPA as a precursor. The fact that EPA addition leads to DHA synthesis together with the evidence that its effects were the same as those shown for DHA, led us to consider the hypothesis that this fatty acid was not acting by itself, but rather due to its metabolization to DHA. To answer this question, cultures were preincubated with CP24879 (CP), a Δ5 and Δ6-desaturase inhibitor before supplementation with EPA. As expected, the presence of the inhibitor prevented the increase in DHA levels in spite of EPA addition and showed a tendency to increase the levels of DPA in cultures supplemented with EPA. We evaluated the effect of the addition of CP on EPA neuroprotection. The addition of CP completely blocked the protective effect of EPA against H2O2-induced apoptosis, and the percentage of apoptotic photoreceptors was the same as that observed in cultures treated with H2O2 without EPA. We also analyzed whether DHA synthesis is required to promote photoreceptors differentiation. For this, we investigated whether incubation with CP affected EPA-induced increase in opsin expression in neuronal cultures. EPA caused an increase in the amount of opsin expression, but preincubation with CP blocked this effect and the amount of opsin + photoreceptors in these cultures was comparable to that observed in controls. Therefore these results indicated that EPA addition to retina neuronal cultures prevented apoptosis of photoreceptors exposed to conditions of oxidative stress and stimulated the differentiation of photoreceptors. EPA effects on photoreceptors were blocked when Δ6-desaturase was inhibited. This implies that it is not EPA by itself that prevents apoptosis and promotes differentiation of cultured photoreceptor but it is DHA synthesized from EPA the fatty acid responsible for these effects. In summary, the main conclusions of this thesis are: - DHA prevents H2O2- induced apoptosis of photoreceptors -DHA decreases the formation of ROS induced by H2O2 - DHA increases the levels of lipid peroxidation in neural retina cultures - DHA activates enzymes involved in the antioxidant defense mechanisms to prevent ROS formation stimulating H2O2 - EPA, like DHA, prevents oxidative stress-induced apoptosis - EPA and not other fatty acids, prevents PQ-induced apoptosis - EPA promotes differentiation of photoreceptors during development in vitro, increasing opsin expression and the formation of apical processes - Cultured rat photoreceptors express Δ6-desaturase - Rat retinal neurons in culture are able to synthesize DHA from EPA - EPA must be metabolized to DHA to protect photoreceptors from apoptosis induced by oxidative stress and for promoting their differentiation.

Introduction: The trade relationship between the European Union (EU) and African coun-tries based on regional groupings, under the framework of Economic Partnership Agree-ment(EPAs) came to play in most countries in January 2008. It replaces the preferential trade treatment granted by the EU under the Lomé convention and Cotonou agreement which allowed African, Carribean and Pacific countries(ACP) greater access to EU markets as a means of leveraging African exports, and encouraging the competitiveness of African economies in the global economy. Method: This work explores basically secondary data sources on EU trade with regional blocs in Africa over the course of the last 27 years. Special attention is given to thematic concerns in the area of intra-regional trade, balance of trade as well as market share. Graphically presentations are utilized in certain instances across the work to serve illustra-tive purposes and to highlight trends established. Conclusion: The study uncovers compelling evidence suggestive of imbalances in trade be-tween the EU and her trading partners in Africa. It is anticipated that these imbalances could shrink export benefits for the African countries concerned. There is reason to be-lieve that problems associated with implementation of EPA‟s, deriving from the distinct development context of the various countries concerned will hamper their development prospects. As it is at the moment, it is quite obvious that these countries will have to live with the consequences of these agreements and strive to cope with new economic realities that seem clearly difficult to reverse.

<p><em><p>Introduction:</p><p>The trade relationship between the European Union (EU) and African coun-tries based on regional groupings, under the framework of Economic Partnership Agree-ment(EPAs) came to play in most countries in January 2008. It replaces the preferential trade treatment granted by the EU under the Lomé convention and Cotonou agreement which allowed African, Carribean and Pacific countries(ACP) greater access to EU markets as a means of leveraging African exports, and encouraging the competitiveness of African economies in the global economy. <em></em></p><p>Method:</p>This work explores basically secondary data sources on EU trade with regional blocs in Africa over the course of the last 27 years. Special attention is given to thematic concerns in the area of intra-regional trade, balance of trade as well as market share. Graphically presentations are utilized in certain instances across the work to serve illustra-tive purposes and to highlight trends established. <em><p>Conclusion:</p>The study uncovers compelling evidence suggestive of imbalances in trade be-tween the EU and her trading partners in Africa. It is anticipated that these imbalances could shrink export benefits for the African countries concerned. There is reason to be-lieve that problems associated with implementation of EPA‟s, deriving from the distinct development context of the various countries concerned will hamper their development prospects. As it is at the moment, it is quite obvious that these countries will have to live with the consequences of these agreements and strive to cope with new economic realities that seem clearly difficult to reverse. </em></em></p>

Hydraulic fracturing of shale has combined traditional oil and gas industry techniques to create significant new reserves in the United States. Poor science, incomplete media coverage and politicization of the issues threaten broad understanding of issues of genuine concern while overstating others. The Environmental Protection Agency should focus on science-based regulation prior to enumerating new rules and should continue to cede primacy to the states where traditional regimes have proven successful in regulating oil and gas. The most critical issues associated with hydraulic fracturing tend to be regional and predicated on local hydrogeology. Surface water disposal and emissions standards need revision and strengthening. Scarce resources should be dedicated to better understanding regional water availability and to heightened awareness of the energy-water nexus. / text

In my study thesis Effect of eikosapentaenoic and dokosahexaenoic acids on expression of selected genes, which participate in modulation of inflammatory reaction at model organism I evaluated expression of genes GPR120, PPARgamma, LBP, ICAM, Il-4, Il-10, Il-1beta and TGF-beta. As model organism was selected pig. The pigs were divided in two groups, the control group was fed with 2,5% addition of palmic oil (P), the second group was fed with 2,5% addition of fish oil. After 70 days long fattening was each group divided into halfs. One half of each group was stimulated LPS (P+ and R+). Liver and adipose tissue were collected, mRNA was isolated (Rneasa Mini Kit), after reverse transcription the expression was measured by quantitative RT-PCR. By almost every genes there was increase in expression after LPS stimulation in groups P+ and R+. between P- and R- the expression was same or a little bit higher in R-. R+ was allways bigger than R-. The hypothesis were that EPA and DHA should reduce expression in inflammation. This hypothesis was not proofed. I recomend further studies with the same model organism to refill the results.