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The dynamics of external contributions to the geomagnetic field is investigated by applying time-frequency methods to magnetic observatory data. Fractal models and multiscale analysis enable obtaining maximum quantitative information related to the short-term dynamics of the geomagnetic field activity. The stochastic properties of the horizontal component of the transient external field are determined by searching for scaling laws in the power spectra. The spectrum fits a power law with a scaling exponent β, a typical characteristic of self-affine time-series. Local variations in the power-law exponent are investigated by applying wavelet analysis to the same time-series. These analyses highlight the self-affine properties of geomagnetic perturbations and their persistence. Moreover, they show that the main phases of sudden storm disturbances are uniquely characterized by a scaling exponent varying between 1 and 3, possibly related to the energy contained in the external field. These new findings suggest the existence of a long-range dependence, the scaling exponent being an efficient indicator of geomagnetic activity and singularity detection. These results show that by using magnetogram regularity to reflect the magnetosphere activity, a theoretical analysis of the external geomagnetic field based on local power-law exponents is possible.
Background: The use of psychoactive substances to neuroenhance cognitive performance is prevalent. Neuroenhancement (NE) in everyday life and doping in sport might rest on similar attitudinal representations, and both behaviors can be theoretically modeled by comparable means-to-end relations (substance-performance). A behavioral (not substance-based) definition of NE is proposed, with assumed functionality as its core component. It is empirically tested whether different NE variants (lifestyle drug, prescription drug, and illicit substance) can be regressed to school stressors.
Findings: Participants were 519 students (25.8 +/- 8.4 years old, 73.1% female). Logistic regressions indicate that a modified doping attitude scale can predict all three NE variants. Multiple NE substance abuse was frequent. Overwhelming demands in school were associated with lifestyle and prescription drug NE.
Conclusions: Researchers should be sensitive for probable structural similarities between enhancement in everyday life and sport and systematically explore where findings from one domain can be adapted for the other. Policy makers should be aware that students might misperceive NE as an acceptable means of coping with stress in school, and help to form societal sensitivity for the topic of NE among our younger ones in general.
Background: Neuroenhancement (NE), the use of psychoactive substances in order to enhance a healthy individual's cognitive functioning from a proficient to an even higher level, is prevalent in student populations. According to the strength model of self-control, people fail to self-regulate and fall back on their dominant behavioral response when finite self-control resources are depleted. An experiment was conducted to test the hypothesis that ego-depletion will prevent students who are unfamiliar with NE from trying it.
Findings: 130 undergraduates, who denied having tried NE before (43% female, mean age = 22.76 +/- 4.15 years old), were randomly assigned to either an ego-depletion or a control condition. The dependent variable was taking an "energy-stick" (a legal nutritional supplement, containing low doses of caffeine, taurine and vitamin B), offered as a potential means of enhancing performance on the bogus concentration task that followed. Logistic regression analysis showed that ego-depleted participants were three times less likely to take the substance, OR = 0.37, p = .01.
Conclusion: This experiment found that trying NE for the first time was more likely if an individual's cognitive capacities were not depleted. This means that mental exhaustion is not predictive for NE in students for whom NE is not the dominant response. Trying NE for the first time is therefore more likely to occur as a thoughtful attempt at self-regulation than as an automatic behavioral response in stressful situations. We therefore recommend targeting interventions at this inter-individual difference. Students without previous reinforcing NE experience should be provided with information about the possible negative health outcomes of NE. Reconfiguring structural aspects in the academic environment (e.g. lessening workloads) might help to deter current users.
We present and discuss the results of crystallographic and electron paramagnetic resonance (EPR) spectroscopic analyses of five tetrachloridocuprate(II) complexes to supply a useful tool for the structural characterisation of the [CuCl4]2− moiety in the liquid state, for example in ionic liquids, or in solution. Bis(benzyltriethylammonium)-, bis(trimethylphenylammonium)-, bis(ethyltriphenylphosphonium)-, bis(benzyltriphenylphosphonium)-, and bis(tetraphenylarsonium)tetrachloridocuprate(II) were synthesised and characterised by elemental, IR, EPR and X-ray analyses. The results of the crystallographic analyses show distorted tetrahedral coordination geometry of all [CuCl4]2− anions in the five complexes and prove that all investigated complexes are stabilised by hydrogen bonds of different intensities. Despite the use of sterically demanding ammonium, phosphonium and arsonium cations to obtain the separation of the paramagnetic Cu(II) centres for EPR spectroscopy no hyperfine structure was observed in the EPR spectra but the principal values of the electron Zeeman tensor, g∥ and g⊥, could be determined. With these EPR data and the crystallographic parameters we were able to carry out a correlation study to anticipate the structural situation of tetrachloridocuprates in different physical states. This correlation is in good agreement with DFT calculations.
Deep into the second half of the twentieth century the traditionalist definition of India as a country of villages remained dominant in official political rhetoric as well as cultural production. In the past two decades or so, this ruralist paradigm has been effectively superseded by a metropolitan imaginary in which the modern, globalised megacity increasingly functions as representative of India as a whole. Has the village, then, entirely vanished from the cultural imaginary in contemporary India? Addressing economic practices from upper-class consumerism to working-class family support strategies, this paper attempts to trace how ‘the village’ resurfaces or survives as a cultural reference point in the midst of the urban.
Various 1,6- and 1,8-naphthalenophanes were synthesized by using the Photo-Dehydro-Diels-Alder (PDDA) reaction of bis-ynones. These compounds are easily accessible from omega-(3-iodophenyl)carboxylic acids in three steps. The obtained naphthalenophanes are axially chiral and the activation barrier for the atropisomerization could be determined in some cases by means of dynamic NMR (DNMR) and/or dynamic HPLC (DHPLC) experiments.
TRAPID
(2013)
Transcriptome analysis through next-generation sequencing technologies allows the generation of detailed gene catalogs for non-model species, at the cost of new challenges with regards to computational requirements and bioinformatics expertise. Here, we present TRAPID, an online tool for the fast and efficient processing of assembled RNA-Seq transcriptome data, developed to mitigate these challenges. TRAPID offers high-throughput open reading frame detection, frameshift correction and includes a functional, comparative and phylogenetic toolbox, making use of 175 reference proteomes. Benchmarking and comparison against state-of-the-art transcript analysis tools reveals the efficiency and unique features of the TRAPID system. TRAPID is freely available at http://bioinformatics.psb.ugent.be/webtools/trapid/.
Background: The linear noise approximation (LNA) is commonly used to predict how noise is regulated and exploited at the cellular level. These predictions are exact for reaction networks composed exclusively of first order reactions or for networks involving bimolecular reactions and large numbers of molecules. It is however well known that gene regulation involves bimolecular interactions with molecule numbers as small as a single copy of a particular gene. It is therefore questionable how reliable are the LNA predictions for these systems.
Results: We implement in the software package intrinsic Noise Analyzer (iNA), a system size expansion based method which calculates the mean concentrations and the variances of the fluctuations to an order of accuracy higher than the LNA. We then use iNA to explore the parametric dependence of the Fano factors and of the coefficients of variation of the mRNA and protein fluctuations in models of genetic networks involving nonlinear protein degradation, post-transcriptional, post-translational and negative feedback regulation. We find that the LNA can significantly underestimate the amplitude and period of noise-induced oscillations in genetic oscillators. We also identify cases where the LNA predicts that noise levels can be optimized by tuning a bimolecular rate constant whereas our method shows that no such regulation is possible. All our results are confirmed by stochastic simulations.
Conclusion: The software iNA allows the investigation of parameter regimes where the LNA fares well and where it does not. We have shown that the parametric dependence of the coefficients of variation and Fano factors for common gene regulatory networks is better described by including terms of higher order than LNA in the system size expansion. This analysis is considerably faster than stochastic simulations due to the extensive ensemble averaging needed to obtain statistically meaningful results. Hence iNA is well suited for performing computationally efficient and quantitative studies of intrinsic noise in gene regulatory networks.
A polymer analogous reaction for the formation of imidazolium and NHC based porous polymer networks
(2013)
A polymer analogous reaction was carried out to generate a porous polymeric network with N-heterocyclic carbenes (NHC) in the polymer backbone. Using a stepwise approach, first a polyimine network is formed by polymerization of the tetrafunctional amine tetrakis(4-aminophenyl)methane. This polyimine network is converted in the second step into polyimidazolium chloride and finally to a polyNHC network. Furthermore a porous Cu(II)-coordinated polyNHC network can be generated. Supercritical drying generates polymer networks with high permanent surface areas and porosities which can be applied for different catalytic reactions. The catalytic properties were demonstrated for example in the activation of CO2 or in the deoxygenation of sulfoxides to the corresponding sulfides.