2,493 research outputs found

    Biochar and ash amendment effects on mine reclamation in the boreal forest

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    Natural re-vegetation of gold mine tailings, the main waste products of ore processing for gold extraction consisting of crushed rock, is difficult due to their high bioavailability of heavy metals, low nutrient status and limited organic carbon 1-3. Charcoal produced from the burning of organic matter through controlled pyrolysis, hereafter referred to as ‘biochar’, has been utilized extensively in agriculture as a climate-friendly option to remediate nutrient-poor and contaminated soils 4,5. Biochar produced from wood is highly recalcitrant, has a large surface area due to its porous structure and can bind nutrients and water, improving soil fertility 5-7. Biochar can also bind undesirable compounds within the soil such as heavy metals, limiting their bioavailability to plants. Please click on the file below for full content of the abstract

    The Political Economy of Populist-Nationalism in Argentina, 1943-55: Peronism as a Transitional Stage in the Development of a Dependent Industrial Economy

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    Focusing on the Peronist period from 1943 to 1955 as the high point of a transitional process between two patterns of dependency on foreign capital, the study explores the dynamics underlying the pendular cycle so characteristic of Latin American political life–the dialectical movement between some variant of populist rule and that based on military power as a means of repressing popular aspirations. Peronism emerged in the context of contradictions within a developmental pattern based on an alliance of the export producing, landowning oligarchy with foreign, primarily British, commercial and financial groups. The developmental model promoted by the Peron government in turn, was geared principally to urban labor and local capitalists producing for the domestic market. The coalition Peronism was based on could only be held together under conditions allowing for increased wages along with higher profits for national capitalists. In the absence of such advantageous conditions, a populist-nationalist regime is driven by its commitment to pursue development within the framework of capitalist social relations to cut back on the consumption levels of its popular base. Such policies result in increased working class militance which undermines capitalist accumulation. This brings the military to power. The military rulers then use the coercive power of the armed forces to back up an economic project serving the interests of the oligarchy and multinational industrial and financial capital. Whereas populist-nationalism used material incentives to gain stable labor relations, the military enforces labor peace through intimidation, torture and murder. This forceful restructuring of the foundation of the nation\u27s economic life not only harms the working class and popular sectors, but also erodes the position of bourgeois sectors based on the production and distribution of wage goods. The stage is set for the reemergence of some variant of populist-nationalism as a formula for exercising state power. Finally, military repression will return once the new regime is unable to provide material benefits for its popular base while also meeting the increased demand from foreign capital for whatever surplus the Argentine economy is able to generate

    Epitope recognition of peptide-imprinted polymers for Regenerating protein 1 (REG1)

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    Molecularly imprinted polymers (MIPs) were developed to replace natural antibodies with a cost-effective and durable synthetic material. Molecular imprinting of proteins conventionally utilizes the whole protein as the template, which is complex (as many different epitopes may be imprinted) and expensive. In this work, seven peptides (13–18 amino acids) were synthesized and used as templates for the imprinting and recognition of Regenerating Protein 1 (REG1). REG1 is involved in the proliferation and differentiation of diverse cell types, and was recently described as a urinary biomarker for pancreatic ductal adenocarcinoma (PDAC). Peptide-imprinted poly(ethylene-co-vinyl alcohol)s (PIPs), containing four different mole fractions of ethylene were cast on screen-printed electrodes to find the optimum composition for both the sensing and the extraction of REG1 in an E. coli culture medium. Peptides with fewer than 16 amino acids and two or three aromatic and hydrophobic groups have a higher affinity for MIPs of poly(ethylene-co-vinyl alcohol) (EVAL) with 27 mol% of ethylene, while those with four aromatic and hydrophobic groups have a higher affinity for MIPs with EVALs that contain 32 mol% of ethylene. The peptide / EVAL combination that maximized both imprinting effectiveness and response to REG1B was the sequence NEDRETWVDADLY imprinted into 32 mol% EVAL. This EVAL composition and template peptide were then modified by incorporation of magnetic nanoparticles, thus extending applications for PIPs to include extraction of REG1 protein from E. coli culture medium

    Phosphatidylinositol transfer protein dictates the rate of inositol trisphosphate production by promoting the synthesis of PIP2

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    AbstractBackground: Phosphatidylinositol transfer protein (PI-TP), which has the ability to transfer phosphatidylinositol (PI) from one membrane compartment to another, is required in the inositol lipid signalling pathway through phospholipase C–β (PLC–β) that is regulated by GTP-binding protein(s) in response to extracellular signals. Here, we test the hypothesis that the principal role of PI-TP is to couple sites of lipid hydrolysis to sites of synthesis, and so to replenish depleted substrate for PLC–β.Results We have designed an experimental protocol that takes advantage of the different rates of release of endogenous PI-TP and PLC-β from HL60 cells permeabilized with streptolysin O. We have examined the kinetics of stimulated inositol lipid hydrolysis in cells depleted of PI-TP, but not of endogenous PLC-β, in the presence and absence of exogenous PI-TP. Linear time-courses were observed in the absence of any added protein, and the rate was accelerated by PI-TP using either guanosine 5′[γ-thio]-triphosphate (GTPγS) or the receptor-directed agonist fMetLeuPhe as activators. In addition, depletion from the cells of both PI-TP and PLC-β isoforms by extended permeabilization (40 minutes) allowed us to control the levels of PLC–β present in the cells. Once again, PI-TP increased the rates of reactions. To identify whether the role of PI-TP was to make available the substrate phosphatidylinositol bisphosphate (PIP2) for the PLC, we examined the synthesis of PIP2 in cells depleted of PI-TP. We found that PI-TP was essential for the synthesis of PIP2.Conclusion The predicted function of PI-TP in inositol lipid signalling is the provision of substrate for PLC–β from intracellular sites where PI is synthesized. We propose that PI-TP is in fact a co-factor in inositol lipid signalling and acts by interacting with the inositol lipid kinases. We hypothesize that the preferred substrate for PLC–β is not the lipid that is resident in the membrane but that provided through PI-TP

    Journal Staff

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    A time-dependent coordinate transformation of a constant coeffcient hyperbolic equation which results in a variable coeffcient problem is considered. By using the energy method, we derive well-posed boundary conditions for the continuous problem. It is shown that the number of boundary conditions depend on the coordinate transformation. By using Summation-by-Parts (SBP) operators for the space discretization and weak boundary conditions, an energy stable finite dieffrence scheme is obtained. We also show how to construct a time-dependent penalty formulation that automatically imposes the right number of boundary conditions. Numerical calculations corroborate the stability and accuracy of the approximations

    Trapped Fermi gases

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    We study the properties of a spin-polarized Fermi gas in a harmonic trap, using the semiclassical (Thomas-Fermi) approximation. Universal forms for the spatial and momentum distributions are calculated, and the results compared with the corresponding properties of a dilute Bose gas.Comment: 6 pages, LaTex, revtex, epsf, submitted to Phys. Rev. A, 6 December 199

    Catastrophic emplacement of giant landslides aided by thermal decomposition: Heart Mountain, Wyoming

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    The Heart Mountain landslide of northwest Wyoming is the largest known sub-aerial landslide on Earth. During its emplacement more than 2000 km3 of Paleozoic sedimentary and Eocene volcanic rocks slid >45 km on a basal detachment surface dipping 2°, leading to 100 yr of debate regarding the emplacement mechanisms. Recently, emplacement by catastrophic sliding has been favored, but experimental evidence in support of this is lacking. Here we show in friction experiments on carbonate rocks taken from the landslide that at slip velocities of several meters per second CO2 starts to degas due to thermal decomposition induced by flash heating after only a few hundred microns of slip. This is associated with the formation of vesicular degassing rims in dolomite clasts and a crystalline calcite cement that closely resemble microstructures in the basal slip zone of the natural landslide. Our experimental results are consistent with an emplacement mechanism whereby catastrophic slip was aided by carbonate decomposition and release of CO2, allowing the huge upper plate rock mass to slide over a ‘cushion’ of pressurized material

    Entering new fields of simulation application - challenges faced in simulation modelling of stroke systems

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    Stroke is a major cause of death and long-term disability world-wide. To improve functional outcome treatment with intravenous tissue plasminogen activator (tPA) is the most effective medical treatment for acute brain infarction within 4.5 hours after the onset of stroke symptoms. Unfortunately, tPA remains substantially underutilized. Acute stroke care organization is among the dominant factors determining undertreatment. Recently, simulation has been suggested and successfully implemented as a tool for optimizing stroke care pathway logistics. Starting from a number of pioneering simulation studies challenges in simulation application and simulation methodology are identified. The definition of a domain specific modelling framework for acute stroke care is advocated to master system complexities, facilitate joint team work in solution finding, organize model data collection and make a further entrance to the field

    Trace levels of sewage effluent are sufficient to increase class 1 integron prevalence in freshwater biofilms without changing the core community

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    Most river systems are impacted by sewage effluent. It remains unclear if there is a lower threshold to the concentration of sewage effluent that can significantly change the structure of the microbial community and its mobile genetic elements in a natural river biofilm. We used novel in situ mesocosms to conduct replicated experiments to study how the addition of low-level concentrations of sewage effluent (nominally 2.5 ppm) affects river biofilms in two contrasting Chalk river systems, the Rivers Kennet and Lambourn (high/low sewage impact, respectively). 16S sequencing and qPCR showed that community composition was not significantly changed by the sewage effluent addition, but class 1 integron prevalence (Lambourn control 0.07% (SE ± 0.01), Lambourn sewage effluent 0.11% (SE ± 0.006), Kennet control 0.56% (SE ± 0.01), Kennet sewage effluent 1.28% (SE ± 0.16)) was significantly greater in the communities exposed to sewage effluent than in the control flumes (ANOVA, F = 5.11, p = 0.045) in both rivers. Furthermore, the difference in integron prevalence between the Kennet control (no sewage effluent addition) and Kennet sewage-treated samples was proportionally greater than the difference in prevalence between the Lambourn control and sewage-treated samples (ANOVA (interaction between treatment and river), F = 6.42, p = 0.028). Mechanisms that lead to such differences could include macronutrient/biofilm or phage/bacteria interactions. Our findings highlight the role that low-level exposure to complex polluting mixtures such as sewage effluent can play in the spread of antibiotic resistance genes. The results also highlight that certain conditions, such as macronutrient load, might accelerate spread of antibiotic resistance genes
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