139 research outputs found

    Die Jesuitenreduktionen in Paraguay im Lichte der kolonialethischen Diskussion

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    Leitmotiv der Arbeit ist die Frage nach dem NĂ€chsten, dem Fremden, dem Unbekannten und dessen Wahrnehmung, die gerade in der heutigen Zeit nichts an ihrer AktualitĂ€t eingebĂŒĂŸt hat. Der Rahmen ist ein historischer, nĂ€mlich die Zeit der „Entgrenzung“ des geographischen Horizonts des Mittelalters und seine insbesondere in Spanien sich unmittelbar stellende Frage nach der RechtmĂ€ĂŸigkeit der Konquista, die sich in der Frage nach dem NĂ€chsten und seinem Menschsein verdichtet. Die Reaktion darauf und die innovative Denkleistung von Vitoria bilden den Ausgangspunkt. Ferner wird auf den Zeitzeugen Las Casas und seinen Kampf fĂŒr die Indios eingegangen. Dieser gipfelt in dem Disput von Valladolid mit seinem Hauptkontrahenten SepĂșlveda. Breiten Raum nimmt das jesuitische Experiment in Paraguay, im speziellen die GuaranĂ­reduktionen ein. Diese bilden die reale historische Grundlage fĂŒr zahlreiche utopische europĂ€ische Projektionen. Es wird versucht, nach einer perspektivenreichen Durchleuchtung des Experiments zu einer abschließenden ethischen WĂŒrdigung zu kommen. In den Schlussgedanken wird der Kreis geschlossen und es finden aktuelle gegenwartsbezogene BezĂŒge statt.The studyÂŽs dominant leitmotif concerns the unknown neighbour, i.e. the stranger and how we perceive him, which is an issue much debated these days. The setting is historical, namely the period of a radical dissolution of boundaries and of expansion of Medieval geographical horizons. Closely connected to these phenomena of transition is the question of the legitimacy of the Spanish Conquista, an ethical dilemma which is of great urgency when considering the unknown neighbour as a fellow human being. Immediate responses to this challenging question and VitoriaÂŽs innovative reflections provide the first impetus to the analysis. A further focus is on the contemporary eyewitness Las Casas and his struggles for the cause of the Indios, a conflict which culminates in the dispute of Valladolid with his main opponent, i.e. SepĂșlveda. The Jesuit experiment in Paraguay, in particular the so-called GuaranĂ­-reductions, is given expansive attention. These experiments are the historical and really existing origins of numerous European utopian fantasies and projections. It is the aim of the study to investigate the experiment from a plurality of perspectives and thus to reach conclusions which do justice to the ethical issues involved. The final section will close the argumentative circle and will attempt to refer to related current concerns

    On the mechanism of RNA phosphodiester backbone cleavage in the absence of solvent

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    Ribonucleic acid (RNA) modifications play an important role in the regulation of gene expression and the development of RNA-based therapeutics, but their identification, localization and relative quantitation by conventional biochemical methods can be quite challenging. As a promising alternative, mass spectrometry (MS) based approaches that involve RNA dissociation in ‘top-down’ strategies are currently being developed. For this purpose, it is essential to understand the dissociation mechanisms of unmodified and posttranscriptionally or synthetically modified RNA. Here, we have studied the effect of select nucleobase, ribose and backbone modifications on phosphodiester bond cleavage in collisionally activated dissociation (CAD) of positively and negatively charged RNA. We found that CAD of RNA is a stepwise reaction that is facilitated by, but does not require, the presence of positive charge. Preferred backbone cleavage next to adenosine and guanosine in CAD of (M+nH)n+ and (M−nH)n− ions, respectively, is based on hydrogen bonding between nucleobase and phosphodiester moieties. Moreover, CAD of RNA involves an intermediate that is sufficiently stable to survive extension of the RNA structure and intramolecular proton redistribution according to simple Coulombic repulsion prior to backbone cleavage into c and y ions from phosphodiester bond cleavage

    Spectral Decomposition of Regulatory Thresholds for Climate-Driven Fluctuations in Hydro- and Wind Power Availability

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    Abstract Climate-driven fluctuations in the runoff and potential energy of surface water are generally large in comparison to the capacity of hydropower regulation, particularly when hydropower is used to balance the electricity production from covarying renewable energy sources such as wind power. To define the bounds of reservoir storage capacity, we introduce a dedicated reservoir volume that aggregates the storage capacity of several reservoirs to handle runoff from specific watersheds. We show how the storage bounds can be related to a spectrum of the climate-driven modes of variability in water availability and to the covariation between water and wind availability. A regional case study of the entire hydropower system in Sweden indicates that the longest regulation period possible to consider spans from a few days of individual subwatersheds up to several years, with an average limit of a couple of months. Watershed damping of the runoff substantially increases the longest considered regulation period and capacity. The high covariance found between the potential energy of the surface water and wind energy significantly reduces the longest considered regulation period when hydropower is used to balance the fluctuating wind power

    Reciprocal regulation of PKA and rac signaling

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    Activated G protein-coupled receptors (GPCRs) and receptor tyrosine kinases relay extracellular signals through spatial and temporal controlled kinase and GTPase entities. These enzymes are coordinated by multifunctional scaffolding proteins for precise intracellular signal processing. The cAMP-dependent protein kinase A (PKA) is the prime example for compartmentalized signal transmission downstream of distinct GPCRs. A-kinase anchoring proteins tether PKA to specific intracellular sites to ensure precision and directionality of PKA phosphorylation events. Here, we show that the Rho-GTPase Rac contains A-kinase anchoring protein properties and forms a dynamic cellular protein complex with PKA. The formation of this transient core complex depends on binary interactions with PKA subunits, cAMP levels and cellular GTP-loading accounting for bidirectional consequences on PKA and Rac downstream signaling. We show that GTP-Rac stabilizes the inactive PKA holoenzyme. However, ÎČ-adrenergic receptor-mediated activation of GTP-Rac–bound PKA routes signals to the Raf-Mek-Erk cascade, which is critically implicated in cell proliferation. We describe a further mechanism of how cAMP enhances nuclear Erk1/2 signaling: It emanates from transphosphorylation of p21-activated kinases in their evolutionary conserved kinase-activation loop through GTP-Rac compartmentalized PKA activities. Sole transphosphorylation of p21-activated kinases is not sufficient to activate Erk1/2. It requires complex formation of both kinases with GTP-Rac1 to unleash cAMP-PKA–boosted activation of Raf-Mek-Erk. Consequently GTP-Rac functions as a dual kinase-tuning scaffold that favors the PKA holoenzyme and contributes to potentiate Erk1/2 signaling. Our findings offer additional mechanistic insights how ÎČ-adrenergic receptor-controlled PKA activities enhance GTP-Rac–mediated activation of nuclear Erk1/2 signaling

    LPMLE3 : a novel 1-D approach to study water flow in streambeds using heat as a tracer

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    We introduce LPMLE3, a new 1-D approach to quantify vertical water flow components at streambeds using temperature data collected in different depths. LPMLE3 solves the partial differential equation for coupled water flow and heat transport in the frequency domain. Unlike other 1-D approaches it does not assume a semi-infinite halfspace with the location of the lower boundary condition approaching infinity. Instead, it uses local upper and lower boundary conditions. As such, the streambed can be divided into finite subdomains bound at the top and bottom by a temperature-time series. Information from a third temperature sensor within each subdomain is then used for parameter estimation. LPMLE3 applies a low order local polynomial to separate periodic and transient parts (including the noise contributions) of a temperature-time series and calculates the frequency response of each subdomain to a known temperature input at the streambed top. A maximum-likelihood estimator is used to estimate the vertical component of water flow, thermal diffusivity, and their uncertainties for each streambed subdomain and provides information regarding model quality. We tested the method on synthetic temperature data generated with the numerical model STRIVE and demonstrate how the vertical flow component can be quantified for field data collected in a Belgian stream. We show that by using the results in additional analyses, nonvertical flow components could be identified and by making certain assumptions they could be quantified for each subdomain. LPMLE3 performed well on both simulated and field data and can be considered a valuable addition to the existing 1-D methods

    A power market-based operation support model for sub-daily hydropower regulation practices

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    Highlights ‱ Investigate the impact of instant energy demand on sub-daily river regime. ‱ Introducing power market impact index. ‱ Introducing system efficiency ratio index. ‱ Provides an efficient tool for sustainable river management. ‱ Assess the interaction of power market and regulation practices.With increasing power production from renewable energy sources, sub-daily variations in energy demand need to be balanced. Today, hydropower is commonly used as balancing power. In this study, we quantified the impact of capacity constraints, in terms of reservoir volume and hydropower capacity, on the potential to comply with instant energy demand. To evaluate the impact, we developed two new metrics, power market impact and system efficiency ratio, which are based on two threshold flow regimes derived from natural flow as lower threshold release and regulated flow (based on hourly energy prices) as upper threshold release. The operation support model comprises 96 different regulation scenarios based on varying combinations of hydropower and reservoir capacities. For each scenario, an hourly water balance was simulated, to obtain the highest complying with upper threshold release based on actual energy demand. We tested the framework on the Kemijoki river with defined thresholds based on the natural flow regime (tributary river Ounasjoki) and the hourly energy price in Finland in 2017, and estimated the impact of regulation on hourly flow regime at the Taivalkoski hydropower station. The annual flow regime impact in 2013, 2014 and 2015 was estimated to be 74%, 84% and 61%, respectively, while the monthly impact varied from 27% to 100%. Our framework for evaluating interactions between the power market and sub-daily regulation practices is a useful novel tool for sustainable river management and can be easily applied to different rivers and regions and evaluated for different timescales

    NALP3 inflammasome upregulation and CASP1 cleavage of the glucocorticoid receptor cause glucocorticoid resistance in leukemia cells

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    Glucocorticoids are universally used in the treatment of acute lymphoblastic leukemia (ALL), and resistance to glucocorticoids in leukemia cells confers poor prognosis. To elucidate mechanisms of glucocorticoid resistance, we determined the prednisolone sensitivity of primary leukemia cells from 444 patients newly diagnosed with ALL and found significantly higher expression of CASP1 (encoding caspase 1) and its activator NLRP3 in glucocorticoid-resistant leukemia cells, resulting from significantly lower somatic methylation of the CASP1 and NLRP3 promoters. Overexpression of CASP1 resulted in cleavage of the glucocorticoid receptor, diminished the glucocorticoid-induced transcriptional response and increased glucocorticoid resistance. Knockdown or inhibition of CASP1 significantly increased glucocorticoid receptor levels and mitigated glucocorticoid resistance in CASP1-overexpressing ALL. Our findings establish a new mechanism by which the NLRP3-CASP1 inflammasome modulates cellular levels of the glucocorticoid receptor and diminishes cell sensitivity to glucocorticoids. The broad impact on the glucocorticoid transcriptional response suggests that this mechanism could also modify glucocorticoid effects in other diseases

    Expression of 11beta-hydroxysteroid dehydrogenase 2 contributes to glucocorticoid resistance in lymphoblastic leukemia cells

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    Synthetic glucocorticoids (GC) form a crucial first-line treatment for childhood acute lymphoblastic leukemia (ALL). However prolonged GC therapy frequently leads to GC-resistance with an unclear molecular mechanism. 11ÎČ-hydroxysteroid dehydrogenase (11ÎČ-HSD) 2 inactivates GCs within cells. Here, we show the association between GC sensitivity and 11ÎČ-HSD2 expression in human T-cell leukemic cell lines. 11ÎČ-HSD2 mRNA and protein levels were considerably higher in GC-resistant MOLT4F cells than in GC-sensitive CCRF-CEM cells. The 11ÎČ-HSD inhibitor, carbenoxolone pre-treatment resulted in greater cell death with prednisolone assesed by methyl-thiazol-tetrazolium assay and Caspase-3/7 assay, suggesting that 11ÎČ-HSD2 is a cause of GC-resistance in ALL

    Is the Hyporheic Zone Relevant beyond the Scientific Community?

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    Rivers are important ecosystems under continuous anthropogenic stresses. The hyporheic zone is a ubiquitous, reactive interface between the main channel and its surrounding sediments along the river network. We elaborate on the main physical, biological, and biogeochemical drivers and processes within the hyporheic zone that have been studied by multiple scientific disciplines for almost half a century. These previous efforts have shown that the hyporheic zone is a modulator for most metabolic stream processes and serves as a refuge and habitat for a diverse range of aquatic organisms. It also exerts a major control on river water quality by increasing the contact time with reactive environments, which in turn results in retention and transformation of nutrients, trace organic compounds, fine suspended particles, and microplastics, among others. The paper showcases the critical importance of hyporheic zones, both from a scientific and an applied perspective, and their role in ecosystem services to answer the question of the manuscript title. It identifies major research gaps in our understanding of hyporheic processes. In conclusion, we highlight the potential of hyporheic restoration to efficiently manage and reactivate ecosystem functions and services in river corridors
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