Energiepflanzenanbau – Wirkungen auf Humusbilanz und Stickstoffhaushalt

Bei der Bewertung der Folgewirkungen des Energiepflanzenanbaus auf Boden und Umwelt ist zwischen den Effekten zu unterscheiden, die von Änderungen in der Landnutzung allgemein bzw. von speziellen Verfahren des Anbaus von Energiepflanzen hervorgerufen werden. Nur die systemimmanenten Effekte des Energiepflanzenanbaus können durch die Verfahrensgestaltung des Selben beeinflusst oder gesteuert werden. Ein wesentliches Element welches den Energiepflanzenanbau vom Anbau traditioneller Marktfrüchte unterscheidet, ist die Rückführung von Gärresten. In diesem Artikel wird daher die Wirkung des Anbaus von Energiepflanzen und die Rückführung von Gärresten auf die Umweltindikatoren Humusbilanz und Stickstoffhaushalt näher untersucht werden. Die Humusbilanzen typischer Energiepflanzenfruchtfolgen sind ohne Ausbringung von Gärresten negativ. Mit Ausbringung von Gärresten sind ausgeglichene Humusbilanzen möglich. Dabei besteht für die Humifizierungs-Faktoren von Gärresten noch Forschungsbedarf. Mit Gärresten kann der Nährstoffkreislauf von Betrieben stärker geschlossen werden. Auf Grund des hohen Mineraldüngeräquivalents kann Mineraldünger gut substituiert werden. Für die Nährstoffe Phosphor, Kalium und Magnesium sind auf dem Nutzungsweg Erntegut–Biogasanlage–Gärrest–Boden keine Verluste zu berücksichtigen. Bei Stickstoff sind nach Berücksichtigung von Verlusten etwa 50 % des Stickstoffs aus dem Erntegut im Boden mineraldüngeräquivalent zur Verfügung

Niklas Luhmann, Carl Schmitt and the Modern Form of the Political

Niklas Luhmann elaborated his account of the political system in a complex, though often implicit, debate with Carl Schmitt. Underlying his systems-theoretical model of politics, and of the legitimacy of politics, is the anti-Schmittian view that modern society's communications about itself are neither coordinated by, nor embodied in, a political centre, and that politics is always an unemphatic aspect of these communications. However, this article proposes an immanent critique of Luhmann's analysis of the political system, and it argues that his theory uses highly selective and puristic techniques to support its limitation of society's politics. If interpreted critically, in fact, Luhmann's political sociology illuminates the specific politicality and political emphasis of certain communications, it underlines the distinction of politics from other systems of social communication, and it calls for a re-insistence on the political as a primary category of social analysis. Copyright © 2007 Sage Publications

Cerebrospinal fluid findings in COVID-19: a multicenter study of 150 lumbar punctures in 127 patients

BACKGROUND Comprehensive data on the cerebrospinal fluid (CSF) profile in patients with COVID-19 and neurological involvement from large-scale multicenter studies are missing so far. OBJECTIVE To analyze systematically the CSF profile in COVID-19. METHODS Retrospective analysis of 150 lumbar punctures in 127 patients with PCR-proven COVID-19 and neurological symptoms seen at 17 European university centers RESULTS: The most frequent pathological finding was blood-CSF barrier (BCB) dysfunction (median QAlb 11.4 [6.72-50.8]), which was present in 58/116 (50%) samples from patients without pre-/coexisting CNS diseases (group I). QAlb remained elevated > 14d (47.6%) and even > 30d (55.6%) after neurological onset. CSF total protein was elevated in 54/118 (45.8%) samples (median 65.35 mg/dl [45.3-240.4]) and strongly correlated with QAlb. The CSF white cell count (WCC) was increased in 14/128 (11%) samples (mostly lympho-monocytic; median 10 cells/µl, > 100 in only 4). An albuminocytological dissociation (ACD) was found in 43/115 (37.4%) samples. CSF L-lactate was increased in 26/109 (24%; median 3.04 mmol/l [2.2-4]). CSF-IgG was elevated in 50/100 (50%), but was of peripheral origin, since QIgG was normal in almost all cases, as were QIgA and QIgM. In 58/103 samples (56%) pattern 4 oligoclonal bands (OCB) compatible with systemic inflammation were present, while CSF-restricted OCB were found in only 2/103 (1.9%). SARS-CoV-2-CSF-PCR was negative in 76/76 samples. Routine CSF findings were normal in 35%. Cytokine levels were frequently elevated in the CSF (often associated with BCB dysfunction) and serum, partly remaining positive at high levels for weeks/months (939 tests). Of note, a positive SARS-CoV-2-IgG-antibody index (AI) was found in 2/19 (10.5%) patients which was associated with unusually high WCC in both of them and a strongly increased interleukin-6 (IL-6) index in one (not tested in the other). Anti-neuronal/anti-glial autoantibodies were mostly absent in the CSF and serum (1509 tests). In samples from patients with pre-/coexisting CNS disorders (group II [N = 19]; including multiple sclerosis, JC-virus-associated immune reconstitution inflammatory syndrome, HSV/VZV encephalitis/meningitis, CNS lymphoma, anti-Yo syndrome, subarachnoid hemorrhage), CSF findings were mostly representative of the respective disease. CONCLUSIONS The CSF profile in COVID-19 with neurological symptoms is mainly characterized by BCB disruption in the absence of intrathecal inflammation, compatible with cerebrospinal endotheliopathy. Persistent BCB dysfunction and elevated cytokine levels may contribute to both acute symptoms and 'long COVID'. Direct infection of the CNS with SARS-CoV-2, if occurring at all, seems to be rare. Broad differential diagnostic considerations are recommended to avoid misinterpretation of treatable coexisting neurological disorders as complications of COVID-19