2,571 research outputs found

    ENVIRONMENTAL AND ECONOMIC IMPACTS OF SOIL EROSION AND FERTILITY MINING IN NORTHERN TANZANIA

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    This paper develops a soil conservation model that is relevant to smallholder farmers who apply little or no fertilizer. Empirical results drawn from northern Tanzania imply that, ignoring fertility mining problem in model specification leads to overestimation of profits for farms that apply little or no fertilizer. The model also shows that, the impact of output price on soil conservation efforts depends on the curvature of the soil erosion function.Soil erosion, Fertility mining, Soil conservation, Price policy, Soil erosion function, Sub-Saharan Africa, Tanzania., Environmental Economics and Policy, Land Economics/Use,

    Um patrimônio esmaecido: a produção açucareira, o Beco do Caminho Curto e a presença quilombola em Joinville (SC)

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    A presença da população negra escravizada e livre, e seus descendentes, é marcada por um forte silenciamento na historiografia oficial de Joinville (SC). A história da cidade muitas vezes é caracterizada por um discurso que privilegia a presença dos colonos europeus que se estabeleceram na região após a criação da Colônia Dona Francisca, em 1851. O artigo busca analisar a história dessas populações e o seu apagamento, considerando o contexto social, econômico e político que envolveu diversos atores. São discutidas novas abordagens sobre a história de Joinville que abarquem a escravidão, a produção açucareira e a posse da terra

    Global Gene Expression Profiling through the Complete Life Cycle of Trypanosoma vivax

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    The parasitic flagellate Trypanosoma vivax is a cause of animal trypanosomiasis across Africa and South America. The parasite has a digenetic life cycle, passing between mammalian hosts and insect vectors, and a series of developmental forms adapted to each life cycle stage. Each point in the life cycle presents radically different challenges to parasite metabolism and physiology and distinct host interactions requiring remodeling of the parasite cell surface. Transcriptomic and proteomic studies of the related parasites T. brucei and T. congolense have shown how gene expression is regulated during their development. New methods for in vitro culture of the T. vivax insect stages have allowed us to describe global gene expression throughout the complete T. vivax life cycle for the first time. We combined transcriptomic and proteomic analysis of each life stage using RNA-seq and mass spectrometry respectively, to identify genes with patterns of preferential transcription or expression. While T. vivax conforms to a pattern of highly conserved gene expression found in other African trypanosomes, (e.g. developmental regulation of energy metabolism, restricted expression of a dominant variant antigen, and expression of 'Fam50' proteins in the insect mouthparts), we identified significant differences in gene expression affecting metabolism in the fly and a suite of T. vivax-specific genes with predicted cell-surface expression that are preferentially expressed in the mammal ('Fam29, 30, 42') or the vector ('Fam34, 35, 43'). T. vivax differs significantly from other African trypanosomes in the developmentally-regulated proteins likely to be expressed on its cell surface and thus, in the structure of the host-parasite interface. These unique features may yet explain the species differences in life cycle and could, in the form of bloodstream-stage proteins that do not undergo antigenic variation, provide targets for therapy

    Long term survivors with metastatic pancreatic adenocarcinoma treated with gemcitabine: a retrospective analysis

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    <p>Abstract</p> <p>Background</p> <p>Metastatic pancreatic adenocarcinoma has a short median overall survival (OS) of 5–6 months. However, a subgroup of patients survives more than 1 year. We analyzed the survival outcomes of this subgroup and evaluated clinical and pathological factors that might affect survival durations.</p> <p>Methods</p> <p>We identified 20 patients with metastatic or recurrent pancreatic adenocarcinoma who received single-agent gemcitabine and had an OS longer than 1 year. Baseline data available after the diagnosis of metastatic or recurrent disease was categorized as: 1) <it>clinical/demographic data </it>(age, gender, ECOG PS, number and location of metastatic sites); 2) <it>Laboratory data </it>(Hematocrit, hemoglobin, glucose, LDH, renal and liver function and CA19-9); 3) <it>Pathologic data </it>(margins, nodal status and grade); 4) <it>Outcomes data </it>(OS, Time to Treatment Failure (TTF), and 2 year-OS). The lowest CA19-9 levels during treatment with gemcitabine were also recorded. We performed a univariate analysis with OS as the outcome variable.</p> <p>Results</p> <p>Baseline logarithm of CA19-9 and total bilirubin had a significant impact on OS (HR = 1.32 and 1.31, respectively). Median OS and TTF on gemcitabine were 26.9 (95% CI = 18 to 32) and 11.5 (95% CI = 9.0 to 14.3) months, respectively. Two-year OS was 56.4%, with 7 patients alive at the time of analysis.</p> <p>Conclusion</p> <p>A subgroup of patients with metastatic pancreatic cancer has prolonged survival after treatment with gemcitabine. Only bilirubin and CA 19-9 levels were predictive of longer survival in this population. Further analysis of potential prognostic and predictive markers of response to treatment and survival are needed.</p

    DNA sequencing as a tool to monitor marine ecological status

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    © 2017 Goodwin, Thompson, Duarte, Kahlke, Thompson, Marques and Caçador. Many ocean policies mandate integrated, ecosystem-based approaches to marine monitoring, driving a global need for efficient, low-cost bioindicators of marine ecological quality. Most traditional methods to assess biological quality rely on specialized expertise to provide visual identification of a limited set of specific taxonomic groups, a time-consuming process that can provide a narrow view of ecological status. In addition, microbial assemblages drive food webs but are not amenable to visual inspection and thus are largely excluded from detailed inventory. Molecular-based assessments of biodiversity and ecosystem function offer advantages over traditional methods and are increasingly being generated for a suite of taxa using a "microbes to mammals" or "barcodes to biomes" approach. Progress in these efforts coupled with continued improvements in high-throughput sequencing and bioinformatics pave the way for sequence data to be employed in formal integrated ecosystem evaluation, including food web assessments, as called for in the European Union Marine Strategy Framework Directive. DNA sequencing of bioindicators, both traditional (e.g., benthic macroinvertebrates, ichthyoplankton) and emerging (e.g., microbial assemblages, fish via eDNA), promises to improve assessment of marine biological quality by increasing the breadth, depth, and throughput of information and by reducing costs and reliance on specialized taxonomic expertise

    Correlating the properties of near-room-temperature first- and second-order magnetocaloric materials

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    Several magnetocaloric materials have been proposed since the discovery of the Giant Magnetocaloric Effect. Although some have great potential as magnetocaloric refrigerants or working materials in thermomagnetic motors/generators, only a few have been tested experimentally or had their properties incorporated into validated mathematical models. While experiments are limited by material costs and specialized equipment to determine magnetic field-dependent properties such as specific heat capacity and magnetization, the development of correlation methods must ensure data quality and resolution over a wide range of conditions to reduce interpolations errors. Aiming to keep the number of baseline experimental data points at a minimum, we propose a fitting procedure to correlate thermomagnetic quantities (i.e., isofield specific heat capacity, magnetization and isothermal entropy change) that is accurate at intermediate (i.e., not directly measured) temperatures and applied magnetic fields. The method has been applied to different first-order materials (La(Fe,Mn,Si) H and MnFeP As ) and second-order materials (Gd and Gd Y ) with a good reproducibility of the isofield specific heat capacity, entropy–temperature diagram, adiabatic temperature change and magnetization behavior around room temperature at applied fields between 0 and 2 T

    Endothelial cell regulation of systemic haemodynamics and metabolism acts through the HIF transcription factors.

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    BackgroundThe vascular endothelium has important endocrine and paracrine roles, particularly in the regulation of vascular tone and immune function, and it has been implicated in the pathophysiology of a range of cardiovascular and inflammatory conditions. This study uses a series of transgenic murine models to explore for the first time the role of the hypoxia-inducible factors, HIF-1α and HIF-2α in the pulmonary and systemic circulations as potential regulators of systemic vascular function in normoxic or hypoxic conditions and in response to inflammatory stress. We developed a series of transgenic mouse models, the HIF-1α Tie2Cre, deficient in HIF1-α in the systemic and pulmonary vascular endothelium and the L1Cre, a pulmonary endothelium specific knockout of HIF-1α or HIF-2α. In vivo, arterial blood pressure and metabolic activity were monitored continuously in normal atmospheric conditions and following an acute stimulus with hypoxia (10%) or lipopolysaccharide (LPS). Ex vivo, femoral artery reactivity was assessed using wire myography.ResultsUnder normoxia, the HIF-1α Tie2Cre mouse had increased systolic and diastolic arterial pressure compared to litter mate controls over the day-night cycle under normal environmental conditions. VO2 and VCO2 were also increased. Femoral arteries displayed impaired endothelial relaxation in response to acetylcholine mediated by a reduction in the nitric oxide dependent portion of the response. HIF-1α L1Cre mice displayed a similar pattern of increased systemic blood pressure, metabolic rate and impaired vascular relaxation without features of pulmonary hypertension, polycythaemia or renal dysfunction under normal conditions. In response to acute hypoxia, deficiency of HIF-1α was associated with faster resolution of hypoxia-induced haemodynamic and metabolic compromise. In addition, systemic haemodynamics were less compromised by LPS treatment.ConclusionsThese data show that deficiency of HIF-1α in the systemic or pulmonary endothelium is associated with increased systemic blood pressure and metabolic rate, a pattern that persists in both normoxic conditions and in response to acute stress with potential implications for our understanding of the pathophysiology of vascular dysfunction in acute and chronic disease
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