TY  - JOUR
A1  - Ngamga, Eulalie Joelle
A1  - Bialonski, Stephan
A1  - Marwan, Norbert
A1  - Kurths, Jürgen
A1  - Geier, Christian
A1  - Lehnertz, Klaus
T1  - Evaluation of selected recurrence measures in discriminating pre-ictal and inter-ictal periods from epileptic EEG data
JF  - Physics Letters A
N2  - We investigate the suitability of selected measures of complexity based on recurrence quantification analysis and recurrence networks for an identification of pre-seizure states in multi-day, multi-channel, invasive electroencephalographic recordings from five epilepsy patients. We employ several statistical techniques to avoid spurious findings due to various influencing factors and due to multiple comparisons and observe precursory structures in three patients. Our findings indicate a high congruence among measures in identifying seizure precursors and emphasize the current notion of seizure generation in large-scale epileptic networks. A final judgment of the suitability for field studies, however, requires evaluation on a larger database.
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.physleta.2016.02.024
SN  - 0375-9601
VL  - 380
IS  - 16
SP  - 1419
EP  - 1425
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bialonski, Stephan
A1  - Caron, David A.
A1  - Schloen, Julia
A1  - Feudel, Ulrike
A1  - Kantz, Holger
A1  - Moorthi, Stefanie D.
T1  - Phytoplankton dynamics in the Southern California Bight indicate a complex mixture of transport and biology
JF  - Journal of Plankton Research
N2  - The stimulation and dominance of potentially harmful phytoplankton taxa at a given locale and time are determined by local environmental conditions as well as by transport to or from neighboring regions. The present study investigated the occurrence of common harmful algal bloom (HAB) taxa within the Southern California Bight, using cross-correlation functions to determine potential dependencies between HAB taxa and environmental factors, and potential links to algal transport via local hydrography and currents. A simulation study, in which Lagrangian particles were released, was used to assess travel times due to advection by prevailing ocean currents in the bight. Our results indicate that transport of some taxa may be an important mechanism for the expansion of their distributions into other regions, which was supported by mean travel times derived from our simulation study and other literature on ocean currents in the Southern California Bight. In other cases, however, phytoplankton dynamics were rather linked to local environmental conditions, including coastal upwelling events. Overall, our study shows that complex current patterns in the Southern California Bight may contribute significantly to the formation and expansion of HABs in addition to local environmental factors determining the spatiotemporal dynamics of phytoplankton blooms.
Y1  - 2016
U6  - http://dx.doi.org/10.1093/plankt/fbv122
SN  - 1464-3774
VL  - 38
IS  - 4
SP  - 1077
EP  - 1091
PB  - Oxford University Press
CY  - Oxford
ER  -