High-performance solution of hierarchical equations of motions for studying energy-transfer in light-harvesting complexes

Excitonic models of light-harvesting complexes, where the vibrational degrees of freedom are treated as a bath, are commonly used to describe the motion of the electronic excitation through a molecule. Recent experiments point toward the possibility of memory effects in this process and require to consider time non-local propagation techniques. The hierarchical equations of motion (HEOM) were proposed by Ishizaki and Fleming to describe the site-dependent reorganization dynamics of protein environments (J. Chem. Phys., 130, p. 234111, 2009), which plays a significant role in photosynthetic electronic energy transfer. HEOM are often used as a reference for other approximate methods, but have been implemented only for small systems due to their adverse computational scaling with the system size. Here, we show that HEOM are also solvable for larger systems, since the underlying algorithm is ideally suited for the usage of graphics processing units (GPU). The tremendous reduction in computational time due to the GPU allows us to perform a systematic study of the energy-transfer efficiency in the Fenna-Matthews-Olson (FMO) light-harvesting complex at physiological temperature under full consideration of memory-effects. We find that approximative methods differ qualitatively and quantitatively from the HEOM results and discuss the importance of finite temperature to achieve high energy-transfer efficiencies.Comment: 14 pages; Journal of Chemical Theory and Computation (2011

Osteopontin and `Melanoma Inhibitory Activity': Comparison of Two Serological Tumor Markers in Metastatic Uveal Melanoma Patients

Background: Evaluation of the protein osteopontin (OPN) as a potential new marker in comparison to melanoma inhibitory activity (MIA) for screening and detection of metastatic uveal melanoma. Methods: Plasma levels of 32 patients with uveal melanoma were analyzed for OPN and MIA by enzyme-linked immunosorbent assay (ELISA). Fourteen of these patients had clinically detectable liver metastases. Results: Median plasma concentration of OPN in patients with metastatic disease was 152.01 ng/ml compared to 47.39 ng/ml in patients without clinically detectable metastases (p < 0.001). The difference between the median MIA plasma levels in patients with (13.11 ng/ml) and patients without (5.64 ng/ml) metastatic disease was also statistically significant (p < 0.001). No correlation could be found between MIA or OPN levels and tumor height in patients without clinically detectable metastases. Conclusion: The proteins MIA and OPN seem to be promising tumor markers for the metastasis screening in patients with uveal melanoma. Copyright (C) 2009 S. Karger AG, Base

Modelling of Oscillations in Two-Dimensional Echo-Spectra of the Fenna-Matthews-Olson Complex

Recent experimental observations of time-dependent beatings in the two-dimensional echo-spectra of light-harvesting complexes at ambient temperatures have opened up the question whether coherence and wave-like behaviour plays a significant role in photosynthesis. We perform a numerical study of the absorption and echo-spectra of the Fenna-Matthews-Olson (FMO) complex in chlorobium tepidum and analyse the requirements in the theoretical model needed to reproduce beatings in the calculated spectra. The energy transfer in the FMO pigment-protein complex is theoretically described by an exciton Hamiltonian coupled to a phonon bath which account for the pigments electronic and vibrational excitations respectively. We use the hierarchical equations of motions method to treat the strong couplings in a non-perturbative way. We show that the oscillations in the two-dimensional echo-spectra persist in the presence of thermal noise and static disorder.Comment: updated text and references, corrected figures 4-7, 20 pages, 7 figure

Are landscape structures insurmountable barriers for foraging bees? A mark-recapture study with two solitary pollen specialist species

To investigate whether landscape structures act as insurmountable barriers for foraging bees, we conducted mark-recapture studies with two pollen-specialist solitary species. Foraging options of the bees were confined to host plant stands across different landscape structures. Differences in altitude of more than 130 m were overcome and forests covering a distance of up to 480 m were crossed by Chelostoma florisomne. A broad river and a motorway with intense traffic did not represent insurmountable barriers for Hoplitis adunca. For C. florisomne, total foraging distances of up to 650 m were measured, but foraging females were recorded predominantly on host plant patches available in relatively close vicinity to their nesting site. While landscape structures might impede foraging in endangered bees, the investigated landscape structures clearly did not act as insurmountable physical barriers for the two common solitary bee species tested in our stud

Mean sea level variability and influence of the North Atlantic oscillation on long-term trends in the German Bight

Changes in the seasonal cycle of mean sea level (MSL) may affect the heights of storm surges and thereby flood risk in coastal areas. This study investigates the intra- and inter-annual variability of monthly MSL and its link to the North Atlantic Oscillation using records from 13 tide gauges located in the German Bight. The amplitudes of the seasonal MSL cycle are not regionally uniform and vary between 20 and 29 cm. Generally, the amplitudes are smaller at the southwestern stations, increasing as one travels to the northeastern part. The amplitudes, as well as the phase of the seasonal cycle, are characterized by a large inter-annual and inter-decadal variability, but no long-term trend could be detected. Nevertheless, in the last two decades annual maximum peaks more frequently occurred in January and February, whereas beforehand an accumulation was detected for the November and December period. These changes in phase in the various sea level time series are consistent with a shift in the annual cycle, which is, however, not significant. The changes are associated with strongly increasing trends in monthly MSL of the winter season (J–M), which are considerably higher compared to the remaining seasons. For the same season, the MSL and North Atlantic Oscillation (NAO) indices show strong similarities, resulting in statistically significant correlations (r ~ 0.7). Hence, these changes are linked with changing pressure conditions over the North Atlantic, which lead to a strong phase of positive values in the NAO index between the 1960’s and 1990’s

The monitoring of the plant species listed in Appendix II and IV of the Habitats Directive in Saxony-Anhalt

Für die Pflanzenarten der Anhänge II und IV der FFH-Richtlinie wurde im Rahmen der FFH-Berichtspflicht Deutschlands an die EU-Kommission ein Monitoringsystem eingerichtet. Hierfür sind die Bundesländer verantwortlich. In Sachsen-Anhalt gibt es aktuell drei Vorkommen von Angelica palustris, eines von Apium repens, 107 von Cypripedium calceolus, 20 von Jurinea cyanoides, fünf von Liparis loeselii und fünf von Orthotrichum rogeri. Für alle Vorkommen dieser Arten wurden in den Jahren 2011/2012 Monitoringflächen eingerichtet (für Cypripedium calceolus nur an 10 Vorkommen, für Jurinea cyanoides an 18 Vorkommen). Diese Vorkommen wurden erfasst und bewertet. Für Coleanthus subtilis, Lindernia procumbens und Luronium natans konnten die in den zurückliegenden Jahren letztmalig bestätigten Vorkommen aktuell (2011/2012) nicht nachgewiesen werden. Aufgrund des natürlicherweise unsteten Auftretens dieser Arten wurden an den letzten bekannten Fundorten Monitoringflächen eingerichtet. Die drei Hauptkriterien des Monitorings: Zustand der Population, Habitatstruktur und Beeinträchtigungen sowie artspezifische Unterkriterien sind durch bundeseinheitliche Vorgaben festgelegt, ebenso die Häufigkeit der Erfassung dieser Kriterien während der jeweils sechsjährigen Berichtsperiode. Darüber hinaus sieht das Landesmonitoring teilweise eine detailliertere Untersuchungstiefe und -frequenz vor.A monitoring system for the plant species listed in Appendix II and IV of the Habitats Directive was installed due to the reporting obligation of Germany to the EU commission. In Germany the federal states are responsible for this monitoring. Actually there exist three localities of Angelica palustris, one of Apium repens, 107 of Cypripedium calceolus, 20 of Jurinea cyanoides, five of Liparis loeselii and five of Orthotrichum rogeri in Saxony-Anhalt. Monitoring sites have been installed at all these localities in 2011/2012 (for Cypripedium calceolus only 10, for Jurinea cyanoides 18). These plant populations were recorded and evaluated. Some species found in the last decade could not be found in 2011–2012: Coleanthus subtilis, Lindernia procumbens and Luronium natans. However, due to the naturally unstable presence of these species monitoring sites are installed at these localities as well. The three main criteria of the monitoring (situation of the population, habitat structure and impairments) as well as specific subcriteria and the monitoring frequency of these parameters are prescribed at the federal level. The specific monitoring of Saxony-Anhalt provides a partly more detailed programme, both concerning investigation criteria and frequency

Mild hypothermia after near drowning in twin toddlers

INTRODUCTION: We report a case of twin toddlers who both suffered near drowning but with different post-trauma treatment and course, and different neurological outcomes. METHODS AND RESULTS: Two twin toddlers (a boy and girl, aged 2 years and 3 months) suffered hypothermic near drowning with protracted cardiac arrest and aspiration. The girl was treated with mild hypothermia for 72 hours and developed acute respiratory dysfunction syndrome and sepsis. She recovered without neurological deficit. The boy's treatment was conducted under normothermia without further complications. He developed an apallic syndrome. CONCLUSION: Although the twin toddlers experienced the same near drowning accident together, the outcomes with respect to neurological status and postinjury complications were completely different. One of the factors that possibly influenced the different postinjury course might have been prolonged mild hypothermia

Predicting soil erosion with RUSLE in mediterranean agricultural systems at catchment scale

Accurate assessment of soil loss is essential for sustainable agricultural production, management and conservation planning, especially in productive rain-fed agro-ecosystems and protected areas. The European Union considers soil as a non-renewable resource and identifies that soil degradation has strong impacts on soil and water resources. In this work the Revised Universal Soil Loss Equation model was applied within a geographic information system in the Estaña catchment (Spanish Pre-Pyrenees) as representative of a Mediterranean agro-ecosystem to elaborate a map of soil erosion at high spatial resolution (5 x 5 m of cell size). The soil erodibility factor (K) is calculated from three different approaches to evaluate the importance of spatial variations in soil texture, field infiltration measurements (Kfs) and amount of coarse fragments. The average value of estimated soil loss for the whole study area is 2.3 Mg ha-1 yr-1 and the highest rates are estimated in crops in steep areas (5.8 Mg ha-1 yr-1) and trails (18.7 Mg ha-1 yr-1). Cultivated soils with high soil erosion rates (higher than 8 Mg ha-1 yr-1) represent 20% of the cultivated area. The average value of soil loss in areas with human disturbances (4.21 Mg ha-1 yr-1) is 4.4 times higher than that estimated for areas with natural vegetation (0.96 Mg ha-1 yr-1). Field validation with 137Cs shows that the estimated value of soil loss in barley fields with the K-Kfs-rocks factor improves the model predictions in comparison with those obtained with the K-texture and K-Kfs factors. The RUSLE model predicts a decrease in soil erosion in fields in accordance with the increase of the age of abandonment. Predicted values of soil erosion and measured soil organic matter and stoniness in old abandoned fields agree with those in areas of natural forest and indicate the recovery of the original conditions of the soil. Statistical analysis highlights that the C factor contributes most of the variability of the values of predicted soil erosion, the K and LS factors contribute in a similar way and the P factor contributes least to the variability of soil erosion. Cultivated soils developed over clay materials in high slope areas are the most susceptible to soil degradation processes in comparison with soils developed over limestones in gentle and medium slope areas. The recovery of terraces in steep fields and conservation of crop residues are proposed as soil conservation practices to reduce the magnitude of soil loss in the study area.This research was financially supported by the following project: “Soil erosion and carbon dynamic in Mediterranean agroecosystems: radioisotopic modelling at different spatial and temporal scales” (MEDEROCAR, CGL2008-00831/BTE) funded by the Spanish Ministry of Science and Innovation.Peer reviewe

Transinsular, transkulturell, transnational, transatlantisch: Karibische Literatur(en)

[No abstract available