Ötzi, the Iceman and his Leather Clothes

Over 5000 years ago, a man climbed up to the icy heights of the glacier in South Tyrol, Italy and died. He was found by accident in 1991, with his clothes and equipment, mummified and frozen: an archaeological sensation and a unique snapshot of a Copper Age man. For several years highly specialised research teams have examined the mummy and all accompanying items. This paper describes how fur and leather clothes of the iceman could have been tanned. Details of the analytical tests undertaken on the 5000 year old leather samples and what they revealed are presented

Latent entrepreneurship across nations

The paper studies latent entrepreneurship across nations. There are three main findings. First, large numbers of people in the industrial countries say they would prefer to be self-employed. Top of the international ranking of entrepreneurial spirit come Poland (with 80% saying so), Portugal and the USA; bottom of the table come Norway (with 27% saying so), Denmark and Russia. Second, for individuals the probability of preferring to be self-employed is strongly decreasing with age, while the probability of being self-employed is strongly increasing with age. Third, we show that self-employed individuals have noticeably higher job satisfaction than the employed, so people's expressed wish to run their business cannot easily be written off as mistaken. We speculate on why so much entrepreneurial spirit lies dormant

Latent entrepreneurship across nations

The paper studies latent entrepreneurship across nations. There are three main findings. First, large numbers of people in the industrial countries say they would prefer to be self-employed. Top of the international ranking of entrepreneurial spirit come Poland (with 80% saying so), Portugal and the USA; bottom of the table come Norway (with 27% saying so), Denmark and Russia. Second, for individuals the probability of preferring to be self-employed is strongly decreasing with age, while the probability of being self-employed is strongly increasing with age. Third, we show that self-employed individuals have noticeably higher job satisfaction than the employed, so people's expressed wish to run their business cannot easily be written off as mistaken. We speculate on why so much entrepreneurial spirit lies dormant

Paternity in mallards: effects of sperm quality and female sperm selection for inbreeding avoidance

Postcopulatory processes might play an important role in sexual selection. In theory, fertilization success could be controlled by females via selection of particular sperm within their reproductive tract, or it could be determined by sperm competition per se. In practice, these two mechanisms are difficult to disentangle. To assess the relative importance of both mechanisms we used artificial insemination in combination with measurements of sperm quality (swimming speed and motility) in mallards. In this species, females often lack behavioral control over copulations and hence may use postcopulatory mechanisms to optimize their reproductive output. One important factor affecting female fitness may be selection of genetically compatible males. To investigate the influence of sperm quality and parental relatedness on paternity we inseminated 12 groups of related females with a sperm mixture containing equal numbers of sperm from a brother and from an unrelated male. Paternity was independent of the relatedness of the siring male to the female but was significantly affected by long-term sperm swimming speed and motility. No interaction between relatedness and sperm quality on paternity was observed. These results suggest that female mallards are not able to select sperm on a purely genetic basis and emphasize the importance of sperm quality in gaining paternit

Directed Cortical Information Flow during Human Object Recognition: Analyzing Induced EEG Gamma-Band Responses in Brain's Source Space

The increase of induced gamma-band responses (iGBRs; oscillations >30 Hz) elicited by familiar (meaningful) objects is well established in electroencephalogram (EEG) research. This frequency-specific change at distinct locations is thought to indicate the dynamic formation of local neuronal assemblies during the activation of cortical object representations. As analytically power increase is just a property of a single location, phase-synchrony was introduced to investigate the formation of large-scale networks between spatially distant brain sites. However, classical phase-synchrony reveals symmetric, pair-wise correlations and is not suited to uncover the directionality of interactions. Here, we investigated the neural mechanism of visual object processing by means of directional coupling analysis going beyond recording sites, but rather assessing the directionality of oscillatory interactions between brain areas directly. This study is the first to identify the directionality of oscillatory brain interactions in source space during human object recognition and suggests that familiar, but not unfamiliar, objects engage widespread reciprocal information flow. Directionality of cortical information-flow was calculated based upon an established Granger-Causality coupling-measure (partial-directed coherence; PDC) using autoregressive modeling. To enable comparison with previous coupling studies lacking directional information, phase-locking analysis was applied, using wavelet-based signal decompositions. Both, autoregressive modeling and wavelet analysis, revealed an augmentation of iGBRs during the presentation of familiar objects relative to unfamiliar controls, which was localized to inferior-temporal, superior-parietal and frontal brain areas by means of distributed source reconstruction. The multivariate analysis of PDC evaluated each possible direction of brain interaction and revealed widespread reciprocal information-transfer during familiar object processing. In contrast, unfamiliar objects entailed a sparse number of only unidirectional connections converging to parietal areas. Considering the directionality of brain interactions, the current results might indicate that successful activation of object representations is realized through reciprocal (feed-forward and feed-backward) information-transfer of oscillatory connections between distant, functionally specific brain areas

Photon Antibunching and Collective Effects in the Fluorescence of Single Bichromophoric Molecules

The fluorescence of individual pairs of perylenemonoimide chromophores coupled via a short rigid linker is investigated. Photon antibunching is reported, indicating collective effects in the fluorescence, which are further substantiated by the observation of collective triplet off times and triplet lifetime shortening. The experimental findings are analyzed in terms of singlet-singlet and singlet-triplet annihilation based on Förster type energy transfer. The results reported here demonstrate that the statistical properties of the emission light of isolated single quantum systems can serve as a hallmark of intermolecular interactions

Epileptic monocular nystagmus and ictal diplopia as cortical and subcortical dysfunction

AbstractWe present the case of a patient with ictal monocular nystagmus and ictal diplopia who became seizure-free after resection of a right frontal focal cortical dysplasia (FCD), type 2B. Interictal neuroophthalmological examination showed several beats of a monocular nystagmus and a spasm of the contralateral eye. An exclusively ictal monocular epileptic nystagmus could be an argument for an exclusively cortical involvement in monocular eye movement control. The interictal findings in our patient, however, argue for an irregular ictal activation of both the cortical frontal eye field and the brainstem