170 research outputs found

    Un modelo de programación linear entera para planificación de corta y de aclareo en masas de Pinus pinaster

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    The study addresses the special case of a management plan for maritime pine (Pinus pinaster Ait.) in common lands. The study area refers to 4,432 ha of maritime pine stands in North Portugal (Perímetro Florestal do Barroso in the county of Ribeira de Pena), distributed among five common lands called baldio areas. Those lands are co-managed by the Official Forest Services and the local communities, essentially for timber production, using empirical guidance. As the current procedure does not guarantee the best thinning and clear-cutting scheduling, it was considered important to develop “easy-to-use” models, supported by optimization techniques, to be employed by the forest managers in the harvest planning of these communitarian forests. Planning of the thinning and clear-cutting operations involved certain conditions, such as: (1) the optimal age for harvesting; (2) the maximum stand density permitted; (3) the minimum volume to be cut; (4) the guarantee of incomes for each of the five baldios in at least a two year period; (5) balanced incomes during the length of the projection period. In order to evaluate the sustainability of the wood resources, a set of constraints lower bounding the average ending age was additionally tested. The problem was formulated as an integer linear programming model where the incomes from thinning and clear-cutting are maximized while considering the constraints mentioned above. Five major scenarios were simulated. The simplest one allows for silvicultural constraints only, whereas the other four consider these constraints besides different management options. Two of them introduce joint management of all common areas with or without constraints addressing balanced distribution of incomes during the plan horizon, whilst the other two consider the same options but for individual management of the baldios. The proposed model is easy to apply, providing immediate advantages for short and mid-term planning periods compared to the empirical methods of harvest planning. Results showed that maximization of production is reached when there are silvicultural restrictions only and when forest management units are regarded as a joint undertaking. The individualized management with a balanced distribution of incomes is an interesting option as it does not drastically reduce the optimal solution while assuring benefits at least every two years.Este estudio trata de desarrollar un plan de gestión para una masa continua de pino marítimo en el Norte de Portugal (Perímetro Florestal do Barroso, en el municipio de Ribeira de Pena). El área de estudio ocupa 4.432 ha y se localiza en cinco zonas comunales denominadas áreas de baldío. Las zonas de baldíos las gestionan los Servicios Oficiales forestales y las comunidades locales, principalmente con el objetivo de producción de madera. La venta del material garantiza un importante rendimiento a las populaciones. Actualmente la gestión se hace de forma empírica, pero se ha considerado importante desarrollar un modelo, basado en técnicas de optimización, que pudiese ser utilizado fácilmente por los gestores. La planificación de las operaciones de corta y de aclareo de estas zonas debe tener en cuenta ciertas condiciones, como por ejemplo: (1) la edad óptima para la corta, (2) la densidad máxima de la masa, (3) el volumen mínimo a cortar, (4) la garantía de ingresos/rendimiento para cada uno de los cinco baldíos, al menos para un periodo de tiempo de dos años, (5) un equilibrio de ingresos/rendimiento durante la duración del plan de gestión. Con el fin de evaluar la sostenibilidad de los recursos madereros de las soluciones óptimas, se ha probado un conjunto de restricciones que limitan la edad final. La programación lineal entera se utilizó para abordar el problema, buscando maximizar los ingresos relacionados con el clareo y corta, teniendo en cuenta las limitaciones mencionadas anteriormente. Se simularon cinco escenarios principales. El más simple tuvo en cuenta solamente limitaciones silvícolas, mientras que los otros dos tienen en cuenta estas limitaciones, además de considerar diferentes opciones de manejo. En dos de ellos se considera la gestión conjunta de todas las zonas, con las opciones de garantizar, o no, una distribución regular de recetas, mientras que en los otros dos se considera la gestión individual de los baldíos, con las opciones ya referidas. Los resultados mostraron que se alcanza la maximización de la producción cuando hay sólo restricciones silvícolas y cuando las unidades de manejo forestal se consideran en conjunto

    A Branch and Bound approach for truss topology design problems with valid inequalities

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    One of the classical problems in the structural optimization field is the Truss Topology Design Problem (TTDP) which deals with the selection of optimal configuration for structural systems for applications in mechanical, civil, aerospace engineering, among others. In this paper we consider a TTDP where the goal is to find the stiffest truss, under a given load and with a bound on the total volume. The design variables are the cross-section areas of the truss bars that must be chosen from a given finite set. This results in a large-scale non-convex problem with discrete variables. This problem can be formulated as a Semidefinite Programming Problem (SDP problem) with binary variables. We propose a branch and bound algorithm to solve this problem. In this paper it is considered a binary formulation of the problem, to take advantage of its structure, which admits a Knapsack problem as subproblem. Thus, trying to improve the performance of the Branch and Bound, at each step, some valid inequalities for the Knapsack problem are included

    Are Anti-Ro52 Antibodies Associated with Pulmonary Involvement in Scleroderma?

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    Abstract Introduction: The presence of anti-Ro52 antibodies has been reported in a wide variety of autoimmune diseases, particularly in myositis, scleroderma and autoimmune liver diseases. Clinical significance of anti-Ro52 antibodies remains controversial. Studies are lacking in clarifying the association of anti-Ro52 with pulmonary involvement in scleroderma. Objectives: To determine if anti-Ro52 antibodies are associated with pulmonary involvement (interstitial, indirect pulmonary hypertension, or both) in scleroderma. Methods: Single center, retrospective study based on immunoblotting panel analysis and patients clinical records. Pulmonary manifestations were sub-grouped in: 1) interstitial (alveolitis and/or fibrosis), 2) pulmonary artery systolic pressure (PASP) ≥40 mmHg plus interstitial pulmonary disease, and 3) isolated PASP≥40 mmHg (purely vascular). Results: Our scleroderma cohort included 200 patients, of which 137 had immunoblotting panels with anti-Ro52 reactivity analysis. The search was conducted between January 2010 and July 2011. The frequency of pulmonary manifestations in patients with positive anti-Ro52 antibodies was 67.7% (n=31), and 60% (n=24) in the negative anti-Ro52 group, showing no significant differences between groups (p=0.621). Still no significant differences were found when pulmonary manifestations were evaluated according to the subgroups (p=0.525). Sensitivity, specificity, positive and negative predictive values of anti-Ro52 reactivity for determining pulmonary involvement in scleroderma were low. Conclusion: No association was found between positive anti-Ro52 antibodies and pulmonary involvement in scleroderma

    A PRÁTICA GEOMORFOLÓGICA NO CONTEXTO ESCOLAR.

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    O estudo do meio está cada vez mais arraigado no contexto escolar e se faz necessário uma prática de ensino diferenciada onde possa desenvolver conceitos e habilidades, especialmente na Geografia. Esta produção é resultado de aplicações pedagógicas na educação básica que se destacaram como um importante material para estimular os alunos no interesse pela Geomorfologia

    Presenca de Dentes Permanentes Irrompidos em Escolares da Regiao Metropolitana de Porto Alegre

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    Foi realizada uma pesquisa de campo em duas escolas da rede pública estadual de Porto Alegre, com a finalidade de verificar a presença de dentes permanentes irrompidos em crianças com faixa etária entre seis a dez anos. Foram examinadas 327 crianças, considerando as variáveis de idade, sexo e raça. Não foi observada diferença significativa para a época de erupção para as variáveis de raça e sexo. Foi observado que aos seis anos de idade uma porcentagem maior de incisivos inferiores (78,7%) irrompeu antes que os primeiros molares inferiores (75,9%), assim como a erupção na arcada inferior antecedeu a da arcada superior. O trabalho teve como referência didática uma ampla literatura sobre os diferentes tópicos relacionados ao processo evolutivo da dentição. A survey was performed in two public schools of Porto Alegre, with the purpose of demonstrate the presence of erupted permanent teeth in children with age ranging from 6 to 10 years old. The sample consisted of 327 patients and the variables examined were age, sex and race. In the 6 year old group, the lowers incisors (78,7%) erupted earlier than the first molars (75,9%) and the teeth on the lower arch erupted before the teeth on upper arch. It was not observed a significant difference (

    Teores de metanol em aguardentes vínicas e bagaceiras portuguesas

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    Comunicação apresentada no 8.º Simpósio de Vitivinicultura do Alentejo que decorreu em Évora de 5 a 7 de Maio de 2010.O metanol é um álcool resultante da degradação das pectinas que ocorre durante o processo de fermentação do vinho e do bagaço, passando para a aguardente durante o processo de destilação. A tecnologia utilizada na preparação dos vinhos e dos bagaços condiciona o seu teor nos destilados. Por razões de toxicidade, o teor de metanol nas aguardentes é limitado a 1000g/hL de álcool puro nas aguardentes bagaceiras e 200g/hL nas aguardentes vínicas (Reg. CE. 110/2008). Assim, antes da colocação das aguardentes no mercado deve ser avaliado o teor deste álcool, o qual é normalmente quantificado por cromatografia-gáslíquido de alta resolução. Neste trabalho são apresentados os teores de metanol de um número considerável de amostras analisadas no nosso laboratório, em 2007, 2008 e 2009. Os resultados obtidos mostram que nenhuma das amostras de aguardente vínica analisada apresentou um teor superior ao limite legal estabelecido. No caso das aguardentes bagaceiras, apenas quatro das amostras analisadas apresentaram teores acima do limite legal

    The impact of breeding Yellow-Legged Gulls on vegetation cover and plant composition of Grey Dune habitats

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    The establishment of large populations of yellow-legged gull Larus michahellis in coastal and urban areas can lead to strong changes in vegetation cover and composition through creating physical disturbance in the vegetation and impacting the soil quality through defecation. In this study, we evaluated the effects of breeding yellow-legged gull populations on tall and short vegetation cover and plant species composition in old (occupied for 13 years) and new (occupied for 3 years) colony sites in grey dunes of the Algarve, southern Portugal. In each site, sampling plots were used to measure the percentage of vegetation cover in areas with and without breeding gulls. In the old colony site, the cover by tall vegetation was substantially reduced and the cover by short vegetation substantially increased in the areas where gulls are breeding in comparison with the adjacent areas. In the new colony sites, there were only minor differences. The increase in cover of short vegetation in the breeding area of the old colony site was mostly by nitrophilous species (Paronychia argentea and Malcolmia littorea) and should be explained by the decrease in vegetation cover of tall plant species and by feces deposition. Tall and slow-growing species Suaeda maritima and Helichrysum italicum covers were negatively affected. Our results showed that yellow-legged gulls affected vegetation cover and composition of grey dunes after 3 years of consecutive breeding, and this should be considered in the management of these habitats where breeding yellow-legged gulls are increasing.info:eu-repo/semantics/publishedVersio

    Influence of soil and organic residue management on biomass and biodiversity of understory vegetation in a Eucalyptus globulus Labill. plantation

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    The objective of this study was to assess the effect of different options of soil preparation and management of harvesting debris on biodiversity and biomass of understory vegetation in plantations of Eucalyptus globulus of Central Portugal. The experiment consisted of six treatments in a replanted area and four treatments in a coppice area with five replicates, following a randomised block design. Surveys of vegetation were performed for 6 years. The proportion of soil cover by plant specieswas estimated and the Shannon–Wiener diversity and equitability indexes determined for each treatment and year. After the 2nd year, the understory vegetation was randomly sampled for above-ground biomass determination.Within the planted area, the removal of slash without soil preparation induced the highest number of species during the experimental period. A similar trend was observed in the coppice area, but less regularly. Significant differences in the proportion of soil cover only occurred within the planted area in the first year, when slash removal without soil preparation induced the highest understory cover. Species diversity was not clearly affected by treatments: significant differences only occurred occasionally and were apparently related to differences in the number of species. Therefore, differences in the equitability index between treatments never were significant. Removal of slash without soil disturbance and broadcast of slash over the soil usually shared the highest biodiversity. Differences between treatments in the amount of understory biomass were never statistically significant during the experimental period. Tendency for a negative influence of soil mobilisation on the amount of understory biomass was observed within the planted area, as well as a similar effect of the treatments consisting of broadcast of slash over the soil surface in the coppice area. In parallel to tree development and canopy closure biomass of that vegetation along the study period was reduced, especially in the planted area

    Cyclin D mediates tolerance of genome-doubling in cancers with functional p53

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    BACKGROUND: Aneuploidy and chromosomal instability (CIN) are common features of human malignancy that fuel genetic heterogeneity. Although tolerance to tetraploidization, an intermediate state that further exacerbates CIN, is frequently mediated by TP53 dysfunction, we find that some genome-doubled tumours retain wild-type TP53. We sought to understand how tetraploid cells with a functional p53/p21-axis tolerate genome-doubling events. METHOD: We performed quantitative proteomics in a diploid/tetraploid pair within a system of multiple independently derived TP53 wild-type tetraploid clones arising spontaneously from a diploid progenitor. We characterized adapted and acute tetraploidization in a variety of flow cytometry and biochemical assays and tested our findings against human tumours through bioinformatics analysis of the TCGA dataset. RESULTS: Cyclin D1 was found to be specifically overexpressed in early but not late passage tetraploid clones, and this overexpression was sufficient to promote tolerance to spontaneous and pharmacologically induced tetraploidy. We provide evidence that this role extends to D-type cyclins and their overexpression confers specific proliferative advantage to tetraploid cells. We demonstrate that tetraploid clones exhibit elevated levels of functional p53 and p21 but override the p53/p21 checkpoint by elevated expression of cyclin D1, via a stoichiometry-dependent and CDK activity-independent mechanism. Tetraploid cells do not exhibit increased sensitivity to abemaciclib, suggesting that cyclin D-overexpressing tumours might not be specifically amenable to treatment with CDK4/6 inhibitors. CONCLUSION: Our study suggests that D-type cyclin overexpression is an acute event, permissive for rapid adaptation to a genome-doubled state in TP53 wild-type tumours and that its overexpression is dispensable in later stages of tumour progression

    A universal assay for detection of oncogenic fusion transcripts by oligo microarray analysis

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    <p>Abstract</p> <p>Background</p> <p>The ability to detect neoplasia-specific fusion genes is important not only in cancer research, but also increasingly in clinical settings to ensure that correct diagnosis is made and the optimal treatment is chosen. However, the available methodologies to detect such fusions all have their distinct short-comings.</p> <p>Results</p> <p>We describe a novel oligonucleotide microarray strategy whereby one can screen for all known oncogenic fusion transcripts in a single experiment. To accomplish this, we combine measurements of chimeric transcript junctions with exon-wise measurements of individual fusion partners. To demonstrate the usefulness of the approach, we designed a DNA microarray containing 68,861 oligonucleotide probes that includes oligos covering all combinations of chimeric exon-exon junctions from 275 pairs of fusion genes, as well as sets of oligos internal to all the exons of the fusion partners. Using this array, proof of principle was demonstrated by detection of known fusion genes (such as <it>TCF3:PBX1</it>, <it>ETV6:RUNX1</it>, and <it>TMPRSS2:ERG</it>) from all six positive controls consisting of leukemia cell lines and prostate cancer biopsies.</p> <p>Conclusion</p> <p>This new method bears promise of an important complement to currently used diagnostic and research tools for the detection of fusion genes in neoplastic diseases.</p
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