The N-P-K soil nutrient balance of portuguese cropland in the 1950s: the transition from organic to chemical fertilization

Agricultural nutrient balances have been receiving increasing attention in both historical and nutrient management research. The main objectives of this study were to further develop balance methodologies and to carry out a comprehensive assessment of the functioning and nutrient cycling of 1950s agroecosystems in Portugal. Additionally, the main implications for the history of agriculture in Portugal were discussed from the standpoint of soil fertility. We used a mass balance approach that comprises virtually all nitrogen (N), phosphorus (P) and potassium (K) inputs and outputs from cropland topsoil for average conditions in the period 1951–56. We found a consistent deficit in N, both for nationwide (−2.1 kg.ha−1.yr−1) and arable crops (−1.6 kg.ha−1.yr−1) estimates, that was rectified in the turn to the 1960 decade. P and K were, in contrast, accumulating in the soil (4.2–4.6 kg.ha−1.yr−1 and 1.0–3.0 kg.ha−1.yr−1, respectively). We observed that the 1950s is the very moment of inflection from an agriculture fertilized predominantly through reused N in biomass (livestock excretions plus marine, plant and human waste sources) to one where chemical fertilizers prevailed. It is suggested that N deficiency played an important role in this transitioninfo:eu-repo/semantics/publishedVersio

Consequences Of On-Track Competition In Railways By Use Of Simulations

Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Trabalho da enfermagem e distúrbio musculoesquelético: revisão das pesquisas sobre o tema Trabajo de la enfermería y disturbio musculoesquelético: revisión de las investigaciones acerca del tema. The nursing work and musculoskeletal disorders: a review of the researches about the theme

Este estudo teve por objetivo identificar a produção brasileira de teses e dissertações sobre os distúrbios musculoesqueléticos em trabalhadores de enfermagem. As publicações foram pesquisadas no banco de teses e dissertações do Portal CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) e nos catálogos da ABEn (Associação Brasileira de Enfermagem), no período de 1978 a 2004. Foram selecionados os resumos de teses e dissertações de acordo com os seguintes critérios: desfecho "musculoesquelético" em população de trabalhadores de enfermagem. Dezoito estudos preencheram os critérios de inclusão. Destes, dois tiveram abordagem qualitativa; um, abordagem qualiquantitativa; e quinze, abordagem quantitativa. Os Cursos de Pós-graduação da Universidade de São Paulo e da Universidade Federal do Rio de Janeiro foram os que se destacaram em produções na temática em tela. Os trabalhos apontam tanto para o crescente adoecimento musculoesquelético dos trabalhadores de enfermagem quanto para as inadequadas condições de trabalho como fator de risco para esse adoecimento.<br>Este estudio tuvo por objetivo identificar la producción brasileña de tesis y disertaciones acerca los disturbios musculoesqueléticos en trabajadores de enfermería. Las publicaciones han sido investigadas en el Banco de Tesis y Disertaciones del Portal CAPES "Coordenação de Aperfeiçoamento de Pessoal de Nível Superior" y en los catálogos de la ABEn - "Associação Brasileira de Enfermagem", en el período de 1978 a 2004. Fueron seleccionados los resúmenes de tesis y disertaciones de acuerdo con los siguientes criterios: el cierre "musculoesquelético" en población de trabajadores de enfermería. Dieciocho estudios cumplían los criterios de inclusión. De estos, dos tuvieron abordaje cualitativo, un cuali-cuantitativo y quince abordaje cuantitativo. Los cursos de Postgrado de la Universidad de São Paulo y de la Universidad Federal del Rio de Janeiro fueron los que se destacaron en producciones en la temática en discusión. Los trabajos señalan tanto para el hecho de adolecer musculoesquelético creciente de los trabajadores de enfermería cuanto para las inadecuadas condiciones de trabajo como factor de riesgo para ese adolecer.<br>This study aimed to identify the Brazilian scientific production (thesis and dissertations) about musculoskeletal disorders in nursing workers. The publications were searched in the Banco de Teses e Dissertações (thesis and dissertations collection) of the Portal CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - (Brazilian Government Agency) and the catalogues of the Associação Brasileira de Enfermagem ABEN (Brazilian Nursing Association). The period researched was 1978-2004. The criterion used to select the thesis and dissertations' abstract was the outcome "musculoskeletal" in nursing population. Eighteen studies matched the criterion. Regarding to the research approach, 2 of them presented a qualitative one, 1 quantitative qualitative one; and 15 quantitative one. The majority of them were from pos-graduated courses of Universidade de São Paulo and Universidade Federal do Rio de Janeiro. The studies pointed out to the growing number of nursing workers who have became sick due to musculoskeletal disorders; as well as to the poor conditions of work as a risk factor for this

Structural variations among monocot emergent and amphibious species from lakes of the semi-arid region of Bahia, Brazil

Temporary lakes are common in the semi-arid region of the State of Bahia and form water mirrors in the rainy season. In this period, various vegetal species appear having different life forms adapted to the seasonality conditions of the rainfall regime. This work surveyed the adaptive anatomical structures of some emergent and amphibious monocot species occurring in these lakes. We studied the anatomy of roots, rhizomes, leaves and scapes of Cyperus odoratus, Oxycaryum cubense, Pycreus macrostachyos (Cyperaceae) - amphibious species; and of Echinodorus grandiflorus (Alismataceae), Eichhornia paniculata (Pontederiaceae) and Habenaria repens (Orchidaceae) - emergent species. The anatomical features of the dermal, fundamental and vascular systems confirming the tendency of the adaptive convergence of these plants to temporary lacustrine the environment include: single layered epidermal cells with a thin cuticle layer in the aerial organs; the presence of air canals in all the organs; few or no supporting tissues; and less numerous conducting elements and thinner cell walls in the xylem. The reduction of the supporting tissues, the number of stomata, which can even be absent, and the number of conducting elements and the degree of cell wall lignification in the xylem of the emergent species is more accentuated than that of the amphibious species. The pattern of distribution of aerenchyma in the roots of the studied species was considered important to distinguish between amphibious and emergent life forms