Regularity of the speed of biased random walk in a one-dimensional percolation model

We consider biased random walks on the infinite cluster of a conditional bond percolation model on the infinite ladder graph. Axelsson-Fisk and H\"aggstr\"om established for this model a phase transition for the asymptotic linear speed $\overline{\mathrm{v}}$ of the walk. Namely, there exists some critical value $\lambda_{\mathrm{c}}>0$ such that $\overline{\mathrm{v}}>0$ if $\lambda\in (0,\lambda_{\mathrm{c}})$ and $\overline{\mathrm{v}}=0$ if $\lambda>\lambda_{\mathrm{c}}$. We show that the speed $\overline{\mathrm{v}}$ is continuous in $\lambda$ on the interval $(0,\lambda_{\mathrm{c}})$ and differentiable on $(0,\lambda_{\mathrm{c}}/2)$. Moreover, we characterize the derivative as a covariance. For the proof of the differentiability of $\overline{\mathrm{v}}$ on $(0,\lambda_{\mathrm{c}}/2)$, we require and prove a central limit theorem for the biased random walk. Additionally, we prove that the central limit theorem fails to hold for $\lambda \geq \lambda_{\mathrm{c}}/2$

Coding of visual object features and feature conjunctions in the human brain

Peer reviewedPublisher PD

Induced gamma band responses predict recognition delays during object identification

Peer reviewedPublisher PD

Aerosol-type classification based on AERONET version 3 inversion products

© Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.This study proposes an aerosol-type classification based on the particle linear depolarization ratio (PLDR) and single-scattering albedo (SSA) provided in the AErosol RObotic NETwork (AERONET) version 3 level 2.0 inversion product. We compare our aerosol-type classification with an earlier method that uses fine-mode fraction (FMF) and SSA. Our new method allows for a refined classification of mineral dust that occurs as a mixture with other absorbing aerosols: pure dust (PD), dust-dominated mixed plume (DDM), and pollutant-dominated mixed plume (PDM). We test the aerosol classification at AERONET sites in East Asia that are frequently affected by mixtures of Asian dust and biomass-burning smoke or anthropogenic pollution. We find that East Asia is strongly affected by pollution particles with high occurrence frequencies of 50 % to 67 %. The distribution and types of pollution particles vary with location and season. The frequency of PD and dusty aerosol mixture (DDM+PDM) is slightly lower (34 % to 49 %) than pollution-dominated mixtures. Pure dust particles have been detected in only 1 % of observations. This suggests that East Asian dust plumes generally exist in a mixture with pollution aerosols rather than in pure form. In this study, we have also considered data from selected AERONET sites that are representative of anthropogenic pollution, biomass-burning smoke, and mineral dust. We find that average aerosol properties obtained for aerosol types in our PLDR–SSA-based classification agree reasonably well with those obtained at AERONET sites representative for different aerosol types.Peer reviewe

Induced gamma-band activity is related to the time point of object identification

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Das Achmer Grasmoor : vegetations- und bodenkundliche Untersuchungen im Hinblick auf die Entwicklung und Sicherung des Gebietes

Das Grasmoor bei Achmer im Landkreis Osnabrück ist ein von Kiefernforsten geprägtes Dünengebiet mit zahlreichen nassen Senken. Es kommen Stillgewässer, Bruchwälder, Anmoore, Nieder- und Übergangsmoore sowie wechselnasse Standorte vor, die eine unterschiedliche Ausprägung in bezug auf die Nährstoffversorgung, den Wasserhaushalt und den Grad der menschlichen Beeinflussung aufweisen. Das Gebiet wurde von April 1993 bis Februar 1994 untersucht. Seit der Unterschutzstellung von Teilen des Gebietes im Jahre 1937 haben sich erhebliche Veränderungen vollzogen. Der Flächenanteil der Feuchtgebiete ist durch die Anlage von Gräben deutlich zurückgegangen. Es sind nahezu überall Degenerationserscheinungen festzustellen, doch sind noch ausgedehnte naturnahe Feuchtgebiete erhalten geblieben, und das Gebiet weist insgesamt einen hohen Wert für den Arten- und Biotopschutz auf. Besonders groß ist derzeit die Gefährdung zweier Moorkomplexe, die nördlich des bestehenden Naturschutzgebietes liegen und von denen nur noch Teilbereiche als wachsendes Übergangsmoor anzusehen sind. Sie stellen potentielle Erweiterungsflächen des Naturschutzgebietes dar. In den letzten 20 Jahren hat eine starke Verbuschung eingesetzt, die seit etwa 1987 extrem zunimmt. Es wird deutlich, daß die bestehende Naturschutzgebietsverordnung keinen effektiven Schutz der Feuchtgebiete darstellt. Zudem zeigt es sich, daß in großen Teilbereichen eine forstliche Nutzung mit den Belangen des Naturschutzes nicht vereinbar ist. Das Grasmoor stellt noch eines der wertvollsten Heideweiherund Moorgebiete im Landkreis Osnabrück mit Pflanzen und Tieren der Nieder-, Übergangs- und Hochmoore dar. Ohne sofortige, umfassende Schutz-, Pflege- und Entwicklungsmaßnahmen ist eine nachhaltige Sicherung vermutlish nicht möglich.The Grasmoor near Achmer in the district of Osnabrück is a sand dune area, influenced by pine forests and rich in wet shallow depressions. There you can find standing water, carr, early bogs, fen and transitory bogs and poikilohydrous sites that reveal a different mark concerning their nutrient supply, water balance and the grade of influence by man. The area was analysed from April 1993 to February 1994. Since parts of the area were put under protection in 1937 there have been immense changes. The humid part of the area has been obviously reduced because of the construction of digs. Nearly everywhere degenerate phenomena can be observed, but there are still expanded humid areas in a good condition and the whole bog is of great importance for the protection of species and biotope. At present there is an extremely high risk for the two bog areas which are situated in the north of the existing nature reserve and from which parts are just growing transitory bogs. They are potential expansion areas of the nature reserve. Over the last twenty years many bushes have begun to grow there and this growth has even been increasing since about 1987. It is obvious that the actual decree for nature reserves cannot guarantee an effective protection of the humid areas. Besides, the situation shows that in large areas of the Grasmoor forestry use is incompatible with interests of nature. The Grasmoor is one of the most precious moorland and bog areas in the district of Osnabrück with wild plants and animals of the fen, transitory and peat bogs. Without immediate steps being taken to protect, take care of and develop the Grasmoor, it's long-term security will be impossible