Unusual DNA binding modes for metal anticancer complexes

DNA is believed to be the primary target for many metal-based drugs. For example, platinum-based anticancer drugs can form specific lesions on DNA that induce apoptosis. New platinum drugs can be designed that have novel modes of interaction with DNA, such as the trinuclear platinum complex BBR3464. Also it is possible to design inert platinum(IV) pro-drugs which are non-toxic in the dark, but lethal when irradiated with certain wavelengths of light. This gives rise to novel DNA lesions which are not as readily repaired as those induced by cisplatin, and provides the basis for a new type of photoactivated chemotherapy. Finally, newly emerging ruthenium(II) organometallic complexes not only bind to DNA coordinatively, but also by H-bonding and hydrophobic interactions triggered by the introduction of extended arene rings into their versatile structures. Intriguingly osmium (the heavier congener of ruthenium) reacts differently with DNA but can also give rise to highly cytotoxic organometallic complexes

Valley polarization effects on the localization in graphene Landau levels

Effects of disorder and valley polarization in graphene are investigated in the quantum Hall regime. We find anomalous localization properties for the lowest Landau level (LL), where disorder can induce wavefunction delocalization (instead of localization), both for white-noise and gaussian-correlated disorder. We quantitatively identify the contribution of each sublattice to wavefunction amplitudes. Following the valley (sublattice) polarization of states within LLs for increasing disorder we show: (i) valley mixing in the lowest LL is the main effect behind the observed anomalous localization properties, (ii) the polarization suppression with increasing disorder depends on the localization for the white-noise model, while, (iii) the disorder induces a partial polarization in the higher Landau levels for both disorder models.Comment: 5 pages, 6 figures, extended version, with 2 new figures adde

Teacher training processes and teachers' competence : A sociological study in the primary school

The paper describes part of a study whose aim was to investigate the relation between modalities of teacher training and modalities of pedagogic practice implemented in the science classroom. The study is focused on primary school context and analyses the evolution of teachers performance in terms of their acquisition of recognition and realisation rules, i.e. coding orientation, to specific scientific learning contexts. Theoretically, the study is based on Bernstein’s theory of pedagogic discourse (1999, 2000)which provided the concepts to characterise the modalities of teacher training and of classroom pedagogic practices and to analyse teachers’ evolution in terms of recognition and realisation rules. The sample was made up of four teachers and their four socially heterogeneous school classes. An action-research methodology was followed.The results suggest that the teacher training implemented was favourable to the teachers’ professional development and their competence to lead all children to a high level of scientific development. The efficiency of the training process has to be mostly attributed to the strong classification of the researcher-teachers relation and to the strong framing of evaluation criteria, selection and sequence, together with weak framing of hierarchical rules and pacing.Fundação Calouste Gulbenkian, Instituto de Inovação Educacional e Fundação para a Ciência e Tecnologia (FCT)

Weak Chaos in large conservative system -- Infinite-range coupled standard maps

We study, through a new perspective, a globally coupled map system that essentially interpolates between simple discrete-time nonlinear dynamics and certain long-range many-body Hamiltonian models. In particular, we exhibit relevant similarities, namely (i) the existence of long-standing quasistationary states (QSS), and (ii) the emergence of weak chaos in the thermodynamic limit, between the present model and the Hamiltonian Mean Field model, a strong candidate for a nonxtensive statistical mechanical approach.Comment: 6 pages, 2 figures. Corrected typos in equation 4. Changed caption in Fig. 1. Corrected references 2 and 6. Acknowledgements adde

Minimal length and the flow of entropy from black holes

The existence of a minimal length, predicted by different theories of quantum gravity, can be phenomenologically described in terms of a generalized uncertainty principle. We consider the impact of this quantum gravity motivated effect onto the information budget of a black hole and the sparsity of Hawking radiation during the black hole evaporation process. We show that the information is not transmitted at the same rate during the final stages of the evaporation and that the Hawking radiation is not sparse anymore when the black hole approaches the Planck mass.Comment: Awarded Honorable Mention in the 2018 Gravity Research Foundation Essay Competitio

Bayesian hierarchical modelling of bacteria growth

Bacterial growth models are commonly used in food safety. Such models permit the prediction of microbial safety and the shelf life of perishable foods. In this paper, we study the problem of modelling bacterial growth when we observe multiple experimental results under identical environmental conditions. We develop a hierarchical version of the Gompertz equation to take into account the possibility of replicated experiments and we show how it can be fitted using a fully Bayesian approach. This approach is illustrated using experimental data from Listeria monocytogenes growth and the results are compared with alternative models. Model selection is undertaken throughout using an appropriate version of the deviance information criterion and the posterior predictive loss criterion. Models are fitted using WinBUGS via R2WinBUGS.Predictive microbiology, Growth models, Gompertz curve, Bayesian hierarchical modelling

Real-time Forecasting of Inflation and Output Growth in the Presence of Data Revisions

We show how to improve the accuracy of real-time forecasts from models that include au-toregressive terms by estimating the models on ‘lightly-revised’data instead of using data from the latest-available vintage. Forecast accuracy is improved by reorganizing the data vintages employed in the estimation of the model in such a way that the vintages used in estimation are of a similar maturity to the data in the forecast loss function. The size of the expected reductions in mean squared error depend on the characteristics of the data revision process. Empirically, we …nd RMSFE gains of 2-4% when forecasting output growth and in‡ation with AR models, and gains of the order of 8% with ADL models.real-time data ; news and noise revisions ; optimal forecasts ; multi-vintage models. JEL Classification: C53

Domain wall pinning and potential landscapes created by constrictions and protrusions in ferromagnetic nanowires

The potential experienced by transverse domain walls (TDWs) in the vicinity of asymmetric constrictions or protrusions in thin Permalloy nanowires is probed using spatially resolved magneto-optical Kerr effect measurements. Both types of traps are found to act as pinning centers for DWs. The strength of pinning is found to depend on the trap type as well as on the chirality of the incoming DW; both types of traps are seen to act either as potential wells or potential barriers, also depending on the chirality of the DW. Micromagnetic simulations have been performed that are in good qualitative agreement with the experimental results.Comment: 6 pages, 7 figure