How are soil use and management reflected by soil organic matter characteristics: a spectroscopic approach

We studied the quantitative and qualitative changes of soil organic matter (SOM) due to different land uses (arable versus grassland) and treatments (organic manure and mineral fertilizer) within an agricultural crop rotation in a long-term field experiment, conducted since 1956 at Ultuna, Sweden, on a Eutric Cambisol. The organic carbon (OC) content of the grassland plot was 1.8 times greater than that of the similarly fertilized Ca(NO3) 2 treated cropped plots. The comparison of two dispersion techniques (a lowenergy sonication and a chemical dispersion which yield inherent soil aggregates) showed that increasing OC contents of the silt-sized fractions were not matched by a linear increase of silt-sized aggregates. This indicated saturation of the aggregates with OC and a limited capacity of particles to protect OC physically. Thermogravimetric analyses suggested an increase of free organic matter with increasing OC contents. Transmission FT-IR spectroscopy showed relative enrichment of carboxylic, aromatic, CH and NH groups in plots with increasing OC contents. The silt-sized fractions contained the largest SOM pool and, as revealed by 13C NMR spectroscopy, were qualitatively more influenced by the plant residue versus manure input than the clay fractions. Alkyl and O-alkyl C in the silt-sized fractions amounted to 57.4% of organic carbon in the animal manure treated plots and 50–53% in the other treatments.We thank the Austrian Science Fund (Fonds zur FÖrderung der wissenschaftlichen Forschung) for funding this bilateral project.Peer reviewe

Persistent order due to transiently enhanced nesting in an electronically excited charge density wave

Non-equilibrium conditions may lead to novel properties of materials with broken symmetry ground states not accessible in equilibrium as vividly demonstrated by non-linearly driven mid-infrared active phonon excitation. Potential energy surfaces of electronically excited states also allow to direct nuclear motion, but relaxation of the excess energy typically excites fluctuations leading to a reduced or even vanishing order parameter as characterized by an electronic energy gap. Here, using femtosecond time- and angle-resolved photoemission spectroscopy, we demonstrate a tendency towards transient stabilization of a charge density wave after near-infrared excitation, counteracting the suppression of order in the non-equilibrium state. Analysis of the dynamic electronic structure reveals a remaining energy gap in a highly excited transient state. Our observation can be explained by a competition between fluctuations in the electronically excited state, which tend to reduce order, and transiently enhanced Fermi surface nesting stabilizing the order

Citalopram Enhances the Activity of Chloroquine in Resistant Plasmodium in Vitro and in Vivo 1

ABSTRACT Citalopram, is an extremely potent inhibitor of neuronal serotonin reuptake. It is structurally unrelated to other antidepressants, but it contains the chemical features associated with reversal of drug resistance and exhibits minimal cardiotoxic side effects and fewer of the anticholinergic and adrenolytic side effects associated with other psychotropic agents. Sensitivity tests to citalopram alone and in combination with chloroquine were performed against chloroquine-resistant and chloroquine-sensitive strains of Plasmodium falciparum and Plasmodium chabaudi. Citalopram alone showed intrinsic activity against the chloroquine-resistant strains of P. falciparum (IC 50 ϭ 1.51 Ϯ .6 M) but only limited activity against the chloroquine-sensitive strain (IC 50 ϭ 33.27 Ϯ 5.87 M) and no activity in vivo. The interaction of chloroquine and citalopram in vitro resulted in a synergistic response in the chloroquineresistant strain but there was no interaction between the drugs in the chloroquine-sensitive strain-a pattern found with other reversal agents. Citalopram enhanced chloroquine susceptibility in both strains of P. chabaudi, however, the potentiating effect was seen at lower doses in the chloroquine-resistant strain. The results of this study suggest that citalopram may have potential as a chemosensitizer in Plasmodium infections on the basis of the low toxicity of citalopram at concentrations potentiating chloroquine activity both in vitro and in vivo. Malaria is a significant source of global morbidity and mortality. Despite the development of new antimalarial agents such as mefloquine, halofantrine and the artemisins, chloroquine remains the drug of choice for the treatment of uncomplicated Plasmodium falciparum malaria infections, due to its low cost, rapid onset of action and its low toxicity. However, the efficacy of chloroquine has diminished due to the emergence and prevalence of chloroquine-resistant strains of P. falciparum (Wensdorfer and Payne, 1991). The rapid development and spread of resistance to chloroquine and other antimalarials, and the tremendous cost of drug development has emphasized the necessity to optimize the use of existing antimalarial agents A number of adjunct drugs have been identified from a wide variety of chemical classes including calcium-channel blockers Citalopram,1-[3-(dimethylamino)propyl]-1-(4-fluorophenyl)-1,3dihydroisobenzofuran-5-carbonite), is an extremely potent inhibitor of neuronal serotonin reuptake The low toxicity coupled with the chemical similarity to chemosensitizers (resistance reversal agents) prompted us to investigate the chemosensitizing effect of citalopram in Plasmodium. In this study, we screened citalopram for chloroquine potentiating activity in chloroquine-resistant and chloroquine sensitive-parasites; both in vitro against P. falciparum and in a rodent malaria model (Plasmodium chabaudi). Methods Effect of Citalopram in Vitro Parasites. Two well-characterized isolates of P. falciparum were used for the drug assays. The chloroquine-resistant FCR-3 strain (IC 50 ϳ 150 nM) (donated by J. Freese, Research in diseases of the Tropical Environment, Durban, South Africa) and the chloroquine

Spielformen im Spielfilm : zur Medienmorphologie des Kinos nach der Postmoderne

Die aktuelle Konjunktur exzentrischen Erzählens im gegenwärtigen Kino ist längst nicht mehr bloß die Illustration einer condition postmoderne, sie verweist vielmehr auf die Hybridisierung von Erzählung und Spiel im digitalen Medienumbruch. Insbesondere im massenattraktiven Spielfilm stehen nicht mehr die selten gewordenen Identifikationsofferten im Zentrum des Interesses und die Zuschauer sorgen sich auch nicht um Interpretationshypothesen, sondern sie finden Vergnügen an Erzählrätseln und verfolgen neugierig das Spiel mit unterschiedlichen Plotvarianten oder paradoxalen Welten. In den Beiträgen dieses Bandes werden Formen dieser Hybridisierung exemplarisch aufgeschlüsselt und genealogisch nachvollzogen

Nitrogen and sulphur management: challenges for organic sources in temperate agricultural systems

A current global trend towards intensification or specialization of agricultural enterprises has been accompanied by increasing public awareness of associated environmental consequences. Air and water pollution from losses of nutrients, such as nitrogen (N) and sulphur (S), are a major concern. Governments have initiated extensive regulatory frameworks, including various land use policies, in an attempt to control or reduce the losses. This paper presents an overview of critical input and loss processes affecting N and S for temperate climates, and provides some background to the discussion in subsequent papers evaluating specific farming systems. Management effects on potential gaseous and leaching losses, the lack of synchrony between supply of nutrients and plant demand, and options for optimizing the efficiency of N and S use are reviewed. Integration of inorganic and organic fertilizer inputs and the equitable re-distribution of nutrients from manure are discussed. The paper concludes by highlighting a need for innovative research that is also targeted to practical approaches for reducing N and S losses, and improving the overall synchrony between supply and demand