Eficiencia de implantación de la secuencia anual trigo - soja, mediante los sistemas de siembra directa y con labranza previa

p.181-186

Flujos de carbono y nitrógeno bajo distintos sistemas de labranza en la región semiárida pampeana

Los contenidos de carbono y nitrógeno orgánicos del suelo están relacionados con su capacidad productiva. Esta relación es esperable que sea más estrecha en suelos de zonas áridas y semiáridas. La cantidad de carbono que puede secuestrar el suelo es, a la vez, de interés por la posibilidad de usar a los suelos como sumideros de carbono y mitigar el efecto invernadero. Esta tesis tiene como objetivo determinar los efectos del sistema de labranza sobre la dinámica del carbono y el nitrógeno en un suelo de una región semiárida. Se realizó un experimento de campo de larga duración en el que se contrastó un manejo tradicional, que empleaba un arado de disco en la labor principal, con un manejo tradicional, que empleaba un arado de disco en la labor principal, con un manejo de siembra directa. Los contenidos de humedad del suelo fueron superiores bajo siembra directa y mayores también los rendimientos de los cultivos que integraban la rotación siendo, consecuentemente, los aportes de carbono en forma de residuos al suelo también mayores. El flujo anual de carbono emitido a la atmósfera como C - CO2 fue similar entre sistemas de labranza, de lo que resultó un balance de carbono neutro bajo siembra directa y negativo bajo labranza con arado. La producción de C - CO2 aumentó con la cantidad de residuos presentes en el suelo y la temperatura y decrecía al incrementarse la cantidad de nitratos. La descomposición de los residuos vegetales y la liberación al suelo de su nitrógeno fue más rápida en el suelo labrado, lo que llevó a mayores niveles de nitratos a la siembra de algunos cultivos en el tratamiento con labranza en casi todos los cultivos integrantes de la rotación. Bajo siembra directa el suelo no perdió carbono durante el experimento mientras que bajo arado de disco el stock de carbono orgánico del suelo decreció. En regiones semiáridas la adopción de siembra directa determina balances de carbono menos negativos que bajo manejos con labranza, por incrementar las entradas de carbono al suelo y no afectar las salidas por respiración heterótrofa.

Resultados del uso del paquete didáctico para el curso de álgebra

El Programa ‘Paquetes Didácticos para los cursos de Matemáticas’ de la Academia Institucional de Matemáticas del Nivel Medio Superior (AIM-NMS-IPN) en colaboración con la Dirección de Tecnología Educativa del Instituto Politécnico Nacional, desarrollaron el Paquete Didáctico de Álgebra para el Nivel Medio Superior que consiste en un libro y un disco compacto con software especializado. El paquete didáctico tiene como propósito dotar al profesor y al estudiante de materiales de calidad, elaborados usando el conocimiento generado por las investigaciones, es un conjunto de materiales que concretan operativamente los cuatro organizadores del currículo: objetivos, contenidos, metodología y evaluación. En particular, las estrategias didácticas y metodológicas, los conocimientos matemáticos y los elementos teóricos para ampliar la cultura matemática de los estudiantes. Estos materiales pretenden apoyar las clases presenciales con materiales innovadores que permitan lograr aprendizaje significativo en los alumnos que cursan esta materia. En este trabajo se presenta un informe de los resultados del cuestionario de opinión aplicado a los alumnos de los grupos piloto con el objetivo de conocer sus impresiones al utilizar este tipo de materiales, así como las mejoras que propongan, todo esto para lograr que el Paquete Didáctico responda realmente a las necesidades de los alumnos.

Predicting the past

H. Jiang, S. Gwynne, E.R. Galea, P. Lawrence, F. Jia and H. Ingason model a disco fire in Gothenburg, Sweden to compare the simulation’s predictions with actual events

Genotypic and antimicrobial characterisation of Propionibacterium acnes isolates from surgically excised lumbar disc herniations

The anaerobic skin commensal Propionibacterium acnes is an underestimated cause of human infections and clinical conditions. Previous studies have suggested a role for the bacterium in lumbar disc herniation and infection. To further investigate this, five biopsy samples were surgically excised from each of 64 patients with lumbar disc herniation. P. acnes and other bacteria were detected by anaerobic culture, followed by biochemical and PCR-based identification. In total, 24/64 (38%) patients had evidence of P. acnes in their excised herniated disc tissue. Using recA and mAb typing methods, 52% of the isolates were type II (50% of culture-positive patients), while type IA strains accounted for 28% of isolates (42% patients). Type III (11% isolates; 21% patients) and type IB strains (9% isolates; 17% patients) were detected less frequently. The MIC values for all isolates were lowest for amoxicillin, ciprofloxacin, erythromycin, rifampicin, tetracycline, and vancomycin (≤1 mg/L). The MIC for fusidic acid was 1-2 mg/L. The MIC for trimethoprim and gentamicin was 2 to ≥4  mg/L. The demonstration that type II and III strains, which are not frequently recovered from skin, predominated within our isolate collection (63%) suggests that the role of P. acnes in lumbar disc herniation should not be readily dismissed.

Limitations of Dental Panoramic Tomography in the anterior mandible

Dental Panoramic Tomography (DPT) is a widely used and valuable examination in dentistry. One area prone to artefacts and therefore misinterpretation is the anterior region of the mandible. This case study discusses a periapical radiolucency related to lower anterior teeth that is discovered to be a radiographic artefact. Possible causes of the artefact include a pronounced depression in the mental region of the mandible or superimposition of intervertebral spaces. Additional limitations of the DPT image include superimposition of radio-opaque structures, reduced image detail compared to intra-oral views and uneven magnification. These problems often make the DPT inappropriate for imaging the anterior mandible.

CLINICAL RELEVANCE: Panoramic radiography is often unsuitable for radiographic examination of the anterior mandible.

POINTS OF VIEW: Multi-Roling Performance in Ireland in the 1990s, Part 1 (Layering)

This series of posts will consider the acting techniques required for this style of performance with reference to four productions from the 1990s in which two actors took on multiple roles: Frank Pig Says Hello (1992), Co-Motion’s stage adaptation of Pat McCabe’s novel; The Butcher Boy, Corca Dorca’s production of Disco Pigs (1996) by Enda Walsh; DubbleJoint’s production of Stones in his Pockets by Marie Jones (1996) and its subsequent award-winning revival which I produced at Belfast’s Lyric Theatre in 1999; and Kabosh’s production of Mojo Mickybo by Owen McCafferty (1998). The discussion will focus primarily on my own empirical exploration of the demands multi-roling places on an actor through the direction of recent revivals of Mojo Mickybo for Belfast’s Chatterbox Theatre Company (2013) and Bedlam Productions (2015).

Folgazões do mogi-abaixo : música, caipiridade e paisagens cantadas

Esta investigação tem por objetivo perceber os protagonismos associados à música raiz na região do Sul de Minas, estado brasileiro de Minas Gerais. Desenvolvido no âmbito da etnomusicologia, trata-se de um estudo etnográfico realizado entre os anos de 2009 e 2012 no município de Jacutinga, localizado no Vale do Sapucaí. Como música raiz entende-se nesse contexto um universo musical que engloba vários “ritmos”, “formas” ou “estilos”, como a moda-de-viola, o pagode-de-viola, a querumana, a guarânia, dentre outros, performado por uma dupla cantando em dueto com acompanhamento da viola caipira. O termo engloba os segmentos música caipira e música sertaneja no sentido em que, para os protagonistas, as classificações convergem. O conceito de paisagem cantada é adotado como principal ferramenta de análise uma vez que no romance – gênero cantado e central da música raiz - a poética-narrativa atua como testemunha da história de um universo associado ao modo de vida rural do centro-sudeste brasileiro. A memória é portanto entextualizada na moda – unidade mínima musical de análise – que ao ser performada evoca um catálogo de elementos identificadores de uma cartografia humana, territorial e sonora, associadas a um universo designado por caipira. O sentido de pertencimento e de identificação com este paradigma promove uma recontextualização destes elementos fazendo emergir novas paisagens e novas práticas onde eles são ressignificados, adquirindo, em alguns casos, o valor de marcos sonoros (ex: o carro-de-boi, o berrante e o monjolo). Paralelamente, o processo de materialização da música que conduziu à sua fixação em disco e ao aparente desaparecimento da situação de performance participativa, transformou a própria música raiz num marco sonoro através do qual a caipiridade é representada.

Brazilian savanna forest : conservation, medicinal reservoir and bioprospecting

This study aimed to analyse the Brazilian savanna forest from a Legal Reserve (LR) area from a perspective of conservation, reservoir of organic carbon and medicinal biomass for a prospective use of native medicinal plants. An ethnobotanical and ethnopharmacological survey was carried out close to a community settled in the rural area in the south of Tocantins, being selected 9 of the most cited species (cajuí- Anacardium othonianum; inharé-Brosimum gaudichaudii; jatobá-Hymenaeae courbaril; jenipapo-Genipa americana, aroeira-Myracrodruon urundeuva; negramina-Siparuna guianensis; barbatimão- Stryphnodendron obovatum; assa peixe-Vernonia brasiliana, embaúba-Cecropia pachystachya). Crude foliar extracts were subjected to a preliminary phytochemical prospection and triage of secondary metabolites with antimicrobial activity of potential interest in health and familiar agriculture. Phenolic compounds, terpenes and flavonoids were detected in the extracts of most species, which suggests the presence of antimicrobial, antioxidant and anti-insect activities. It was evident the need to better know the LR as a reservoir of medicinal biomass in an area under ecological tension where 35% (610ha) of the property is LR and should be protected by law. Therefore, a forest inventory of live woody species was performed using the allometric or indirect method. This identified a rare remnant of Semidecidual Seasonal Forest amidst the largest world savannah, the Cerrado biome. An analysis of the forest average productivity per basal area (m².ha), aerial live biomass (ton.ha-1) and carbon stock was carried out. The forest fragment was considered relatively rich in species and diversity, although showing signs of disturbance and dominance by a few species. Its horizontal structure suggests biotic regeneration conditions. It is an important reservoir of medicinal plants. Of the families (57.5%) presenting medicinal species, 19 from a total of 33 are represented in the area and contain 44% (27) of the total species (61) and 63% (432) of the total individuals catalogued. Medicinal species have ecological importance for the equilibrium of the local flora and represent 80% of the 10 species with higher Importance Value Index (IVI): Tetragastris altissima, Chrysophyllum marginatum, Oenocarpus distichus, Sclerolobium paniculatum, Simarouba versicolor, Alibertia macrophylla, Siparuna guianensis, Maprounea guianensis, Licania parvifolia e Physocalymma scaberrimum. Medicinal productivity was high for this type of phytophysionomy: 183,2 ton. ha-1 of biomass and 91,51 ton. ha-1 of carbon representing 66% of the total biomass and carbon of this Cerrado forest. From this stage S. guianensis (Siparunaceae) was selected for performing bioassays in order to verify its biological activity against microorganisms of health and agricultural relevance. This is a native aromatic medicinal plant recommended as priority for conservation, with local popular medicinal validation and availability of medicinal feedstock (3300 Kg.ha-1), with the foliar fraction giving 38Kg/ha of crude extract and 5L/ha of essential oil. Foliar crude extracts and essential oil were obtained and tested in vitro using a disk diffusion bioassay. Different concentrations of these natural products were tested against gram-positive bacteria (Staphylococcus aureus ATCC 29213), gram-negative bacteria (Escherichia coli ATCC 25922 and ATCC 35218; Pseudomonas aeruginosa ATCC 10145) and fungi (Candida albicans ATCC 6258 e Fusarium oxysporum). The essential oil inhibited the growth of S. aureus in its crude concentration (380μg.mL-1), as well as diluted to half (190μg.mL-1) and a quarter strength (95μg.mL-1). It’s likely that such action is due to sesquiterpenes major components, such as bisabolol and bisabolene (10.35%), measured by gas chromatography (GC-MS, GC-FID). Extracts did not exhibit any antimicrobial activity against the microorganisms tested. The native medicinal plants prospective market is an alternative that favours the conservation of biodiversity while generating benefits for the development of sustainable family productive activities within local ecosystems instead of the current inappropriate uses. This strengthens conservation policies of Legal Reserve in rural settlements and is in agreement with public policy on global warming and climate changes.

Functional analysis of String/CDC25 phosphatase in post-mitotic neurons

Cell cycle and differentiation are two highly coordinated processes during organ development. Recent studies have demonstrated that core cell cycle regulators also play cell cycle-independent functions in post-mitotic neurons, and are essential for the maintenance of neuronal homeostasis. CDC25 phosphatases are well-established CDK activators and their activity is mainly associated to proliferating tissues. The expression and activity of mammalian CDC25s has been reported in adult brains. However, their physiological relevance and the potential substrates in a non-proliferative context have never been addressed. string (stg) encodes the Drosophila CDC25 homolog. Previous studies from our group showed that stg is expressed in photoreceptors (PRs) and in lamina neurons, which are two differentiated cell types that compose the fly visual system. The aims of this work are to uncover the function of stg and to identify its potential neuronal substrates, using the Drosophila visual system as a model. To gain insight into the function of stg in a non-dividing context we used the GAL4/UAS system to promote downregulation of stg in PR-neurons, through the use of an RNAi transgene. The defects caused by stg loss-of-function were evaluated in the developing eye imaginal disc by immunofluorescence, and during adult stages by scanning electron microscopy. This genetic approach was combined with a specific proteomic method, two-dimensional difference gel electrophoresis (2D-DIGE), to identify the potential substrates in PR-cells. Our results showed that stg downregulation in PRs affects the well-patterned retina organization, inducing the loss of apical maintenance of PR-nuclei on the eye disc, and ommatidia disorganization. We also detected an abnormal accumulation of cytoskeletal proteins and a disruption of the axon structure. As a consequence, the projection of PR-axons into the lamina and medulla neuropils of the optic lobe was impaired. Upon stg downregulation, we also detected that PR-cells accumulate Cyclin B. Although the rough eye phenotype observed upon stg downregulation suggests neurodegeneration, we did not detect neuronal death during larval stages, suggesting that it likely occurs during pupal stages or during adulthood. By 2D-DIGE, we identified seven proteins which were differentially expressed upon stg downregulation, and are potential neuronal substrates of Stg. Altogether, our observations suggest that Stg phosphatase plays an essential role in the Drosophila visual system neurons, regulating several cell components and processes in order to ensure their homeostasis.

Application of LOICZ DPSIR framework to South asia Basins and developing typology for coastal vulnerability in South Asia

Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2007

Endocrine regulation of extracellular matrix proteins in calcified tissue in teleost fish

Tese dout., Biologia, Universidade do Algarve, 2005

Role of the different actin genes during extrusion of capping protein mutant cells in the Drosophila wing blade epithelium

Dissertação mest., Biotecnologia, Universidade do Algarve, 2008

Fito- e bacterioplâncton em albufeiras dominadas por cianobactérias no Algarve

Dissertação de mest., Biologia Molecular e Microbiana, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2011

Insights into molecular and cellular events involved in normal and pathological vertebral development and fusion using zebrafish as model organism

The vertebral column and its units, the vertebrae, are fundamental features, characteristic of all vertebrates. Developmental segregation of the vertebral bodies as articulated units is an intrinsic requirement to guarantee the proper function of the spine. Whenever these units become fused either during development or postsegmentation, movement is affected in a more or less severe manner, depending on the number of vertebrae affected. Nevertheless, fusion may occur as part of regular development and as a physiological requirement, like in the tetrapod sacrum or in fish posterior vertebrae forming the urostyle. In order to meet the main objective of this PhD project, which aimed to better understand the molecular and cellular events underlying vertebral fusion under physiological and pathological conditions, a detailed characterization of the vertebral fusion occurring in zebrafish caudal fin region was conducted. This showed that fusion in the caudal fin region comprised 5 vertebral bodies, from which, only fusion between [PU1++U1] and ural2 [U2+] was still traceable during development. This involved bone deposition around the notochord sheath while fusion within the remaining vertebral bodies occur at the level of the notochord sheath, as during the early establishment of the vertebral bodies. A comparison approach between the caudal fin vertebrae and the remaining vertebral column showed conserved features such as the presence of mineralization related proteins as Osteocalcin were identified throughout the vertebral column, independently on the mineralization patterns. This unexpected presence of Osteocalcin in notochord sheath, here identified as Oc1, suggested that this gene, opposing to Oc2, generally associated with bone formation and mature osteoblast activity, is potentially associated with early mineralization events including chordacentrum formation. Nevertheless, major differences between caudal fin region and anterior vertebral bodies considering arch histology and mineralization patterns, led us to use RA as an inductive factor for vertebral fusion, allowing a direct comparison of equivalent structures under normal and fusion events. This fusion phenotype was associated with notochord sheath ectopic mineralization instead of ectopic perichordal bone formation related with increased osteoblast activity, as suggested in previous reports. Additionally, alterations in ECM content, cell adhesion and blood coagulation were discussed as potentially related with the fusion phenotype. Finally, Matrix gla protein, upregulated upon RA treatment and shown to be associated with chordacentrum mineralization sites in regular development, was further described considering its potential function in vertebral formation and pathological fusion. Therefore with this work we propose zebrafish caudal fin vertebral fusion as a potential model to study both congenital and postsegmentation fusion and we present candidate factors and genes that may be further explored in order to clarify whether we can prevent vertebral fusion.