The direct synthesis of crosslinked polymeric azomethines

Char yields of synthesized crosslinked polymeric azomethine

The effects of leaching from alkaline red mud on soil biota: modelling the conditions after the Hungarian red mud disaster

A soil column experiment was set up to investigate the effect of red mud from Ajka (Hungary) on a typical soil profile from the concerned area. The chemical changes caused by the leachate of the red mud and the effects of these changes on living organisms were assessed. Ecotoxicological tests with Vibrio fischeri, Sinapis alba and Folsomia candida were performed and the number of aerobic heterotrophic microorganisms was determined. The total, plant available, exchangeable and water soluble fractions of Na, Mo, Cu, and Cr increased in the soil mostly due to their leaching from the red mud layer and partly to the increase of the pH and DOC concentration. The chemical changes had significant effects on the test organisms only in the 0 – 30 cm soil layer except for F. candida that had a lower survival rate also in the 30 – 50 cm soil layer. There were no severe toxic effects detected on the test organisms. Furthermore in case of the aerobic heterotrophic cell number and S. alba germination a stimulating effect was revealed. However, the red mud itself was toxic, therefore the performed ecotoxicology tests have justified the removal of red mud from the soil surface after the disaster

Anthropogenic and natural ground deformation in the Hengill geothermal area, Iceland

We investigate crustal deformation due to the extraction of water and steam from a high-enthalpy geothermal reservoir; a common occurrence, yet not well understood. The cause of this deformation can be a change in pressure or in temperature in the reservoir, both of which can be caused by extraction or injection of geothermal fluids. Our study area, the Hengill mountains in SW Iceland, is an active volcanic center and a plate triple junction that hosts two power plants producing geothermal energy. This combination of natural and anthropogenic processes causes a complex displacement field at the surface. We analyze geodetic data—Global Navigation Satellite System and Interferometric Synthetic Aperture Radar—to obtain the surface velocity field, which we then simulate using an inverse modeling approach. We focus on the deformation around the geothermal power plants but need to model the regional tectonic and volcanic deformation as well, because the signals are overlapping. We find that plate motion and a deep contracting body can explain the broad scale signal in the area. Local deformation near the two power plants, Hellisheidi and Nesjavellir, can be explained by extraction of geothermal fluids. We estimate reservoirs extending from 0.6 to 3.0 km depth at Hellisheidi, and 1.0 to 3.0 km depth at Nesjavellir for observed pressure decrease rates of 0.25 MPa/yr and 0.1 MPa/yr, respectively. We find that the main cause for the subsidence in the geothermal area is the observed pressure drawdown

Teleology and Realism in Leibniz's Philosophy of Science

This paper argues for an interpretation of Leibniz’s claim that physics requires both mechanical and teleological principles as a view regarding the interpretation of physical theories. Granting that Leibniz’s fundamental ontology remains non-physical, or mentalistic, it argues that teleological principles nevertheless ground a realist commitment about mechanical descriptions of phenomena. The empirical results of the new sciences, according to Leibniz, have genuine truth conditions: there is a fact of the matter about the regularities observed in experience. Taking this stance, however, requires bringing non-empirical reasons to bear upon mechanical causal claims. This paper first evaluates extant interpretations of Leibniz’s thesis that there are two realms in physics as describing parallel, self-sufficient sets of laws. It then examines Leibniz’s use of teleological principles to interpret scientific results in the context of his interventions in debates in seventeenth-century kinematic theory, and in the teaching of Copernicanism. Leibniz’s use of the principle of continuity and the principle of simplicity, for instance, reveal an underlying commitment to the truth-aptness, or approximate truth-aptness, of the new natural sciences. The paper concludes with a brief remark on the relation between metaphysics, theology, and physics in Leibniz

Structural relaxation of E' gamma centers in amorphous silica

We report experimental evidence of the existence of two variants of the E' gamma centers induced in silica by gamma rays at room temperature. The two variants are distinguishable by the fine features of their line shapes in paramagnetic resonance spectra. These features suggest that the two E' gamma differ for their topology. We find a thermally induced interconversion between the centers with an activation energy of about 34 meV. Hints are also found for the existence of a structural configuration of minimum energy and of a metastable state.Comment: 4 pages, 2 figures, submitted to Phys. Rev. Let

Influence of myocardial oxygen demand on the coronary vascular response to arterial blood gas changes in humans

It remains unclear if the human coronary vasculature is inherently sensitive to changes in arterial PO2 and PCO2 or if coronary vascular responses are the result of concomitant increases in myocardial O2 consumption/demand (MVO2). We hypothesized that the coronary vascular response to PO2 and PCO2 would be attenuated in healthy men when MVO2 was attenuated with β1-adrenergic receptor blockade. Healthy men (n=11; age: 25 {plus minus} 1 years) received intravenous esmolol (β1-adrenergic receptor antagonist) or volume-matched saline in a double-blind, randomized, crossover study, and were exposed to poikilocapnic hypoxia, isocapnic hypoxia, and hypercapnic hypoxia. Measurements made at baseline and following 5-min of steady state at each gas manipulation included left anterior descending coronary blood velocity (LADV; Doppler echocardiography), heart rate and arterial blood pressure. LADV values at the end of each hypoxic condition were compared between esmolol and placebo. Rate pressure product (RPP) and left-ventricular mechanical energy (MELV) were calculated as indices of MVO2. All gas manipulations augmented RPP, MELV, and LADV but only RPP and MELV were attenuated (4-18%) following β1-adrenergic receptor blockade (P<0.05). Despite attenuated RPP and MELV responses, β1-adrenergic receptor blockade did not attenuate the mean LADV vasodilatory response when compared to placebo during poikilocapnic hypoxia (29.4{plus minus}2.2 vs. 27.3{plus minus}1.6 cm/s) and isocapnic hypoxia (29.5{plus minus}1.5 vs. 30.3{plus minus}2.2 cm/s). Hypercapnic hypoxia elicited a feed-forward coronary dilation that was blocked by β1-adrenergic receptor blockade. These results indicate a direct influence of arterial PO2 on coronary vascular regulation that is independent of MVO2

Conversion of Cerrado into agricultural land in the south-western amazon: carbon stocks and soil fertility.

Mudanças de uso da terra e práticas de manejo modificam a dinâmica do C e a fertilidade do solo. Este estudo avaliou as implicações dos sistemas de cultivo (NT e CT) nos estoques de C e de nutrientes e identificou inter-relações entre estes estoques e outros atributos da fertilidade do solo em Latossolo após a mudança do uso da terra no cerrado amazônico. Os estoques de C e de nutrientes (P, K, Ca e Mg) ajustados pela massa equivalente do solo sob cerrado (CE), foram maiores principalmente sob NT. Após a adoção do NT, exceto em 2NT, os estoques de C foram maiores em relação às demais áreas avaliadas. Correlações entre estoques de C e de nutrientes revelaram algumas correlações positivas com Ca e Mg nas áreas sob NT, devido ao uso continuo de calcário, à maior quantidade de resíduos culturais e ao não revolvimento do solo, associado à correlações positivas com CTC, saturação por bases e pH. A correlação positiva (r = 0,91, p < 0,05) entre estoques de C e CTC em CE indica a importante contribuição da MOS na CT de solos tropicais, embora os sítios de troca estejam ocupados principalmente por H + Al. Estoques de P e K mostraram correlações positivas com estoques de C em CE (0,81 e 0,82; respectivamente), indicando a alta relação de P e K com a MOS em ecossistemas naturais. A alta variabilidade espacial associada à aplicação de fertilizantes (P e K) no sulco de plantio pode ter mascarado os resultados dos estoques. A principal fonte destes nutrientes para o solo foi o fertilizante aplicado e não a MOS

Excess Higgs Production in Neutralino Decays

The ATLAS and CMS experiments have recently claimed discovery of a Higgs boson-like particle at ~5 sigma confidence and are beginning to test the Standard Model predictions for its production and decay. In a variety of supersymmetric models, a neutralino NLSP can decay dominantly to the Higgs and the LSP. In natural SUSY models, a light third generation squark decaying through this chain can lead to large excess Higgs production while evading existing BSM searches. Such models can be observed at the 8 TeV LHC in channels exploiting the rare diphoton decays of the Higgs produced in the cascade decay. Identifying a diphoton resonance in association with missing energy, a lepton, or b-tagged jets is a promising search strategy for discovery of these models, and would immediately signal new physics involving production of a Higgs boson. We also discuss the possibility that excess Higgs production in these SUSY decays can be responsible for enhancements of up to 50% over the SM prediction for the observed rate in the existing inclusive diphoton searches, a scenario which would likely by the end of the 8 TeV run be accompanied by excesses in the diphoton + lepton/MET and SUSY multi-lepton/b searches and a potential discovery in a diphoton + 2b search.Comment: 42 pages, 19 figure

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s=8 TeV proton-proton collision data

A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector