A mathematically assisted reconstruction of the initial focus of the yellow fever outbreak in Buenos Aires (1871)

We discuss the historic mortality record corresponding to the initial focus of the yellow fever epidemic outbreak registered in Buenos Aires during the year 1871 as compared to simulations of a stochastic population dynamics model. This model incorporates the biology of the urban vector of yellow fever, the mosquito Aedes aegypti, the stages of the disease in the human being as well as the spatial extension of the epidemic outbreak. After introducing the historical context and the restrictions it puts on initial conditions and ecological parameters, we discuss the general features of the simulation and the dependence on initial conditions and available sites for breeding the vector. We discuss the sensitivity, to the free parameters, of statistical estimators such as: final death toll, day of the year when the outbreak reached half the total mortality and the normalized daily mortality, showing some striking regularities. The model is precise and accurate enough to discuss the truthfulness of the presently accepted historic discussions of the epidemic causes, showing that there are more likely scenarios for the historic facts.Comment: 25 pages, 12 figure

Role of critical spin fluctuations in ultrafast demagnetization of transition-metal rare-earth alloys

Ultrafast magnetization dynamics induced by femtosecond laser pulses have been measured in ferrimagnetic Co0.8Gd0.2, Co.74Tb.26 and Co.86Tb.14 alloys. Using element sensitivity of X-ray magnetic circular dichroism at the Co L3, Tb M5 and Gd M5 edges we evidence that the demagnetization dynamics is element dependent. We show that a thermalization time as fast as 280 fs is observed for the rare-earth in the alloy, when the laser excited state temperature is below the compensation temperature. It is limited to 500 fs when the laser excited state temperature is below the Curie temperature (Tc). We propose critical spin fluctuations in the vicinity of TC as the mechanism which reduces the demagnetization rates of the 4f electrons in transition-metal rare-earth alloys whereas at any different temperature the limited demagnetization rates could be avoided.Comment: 11 pages, 4 figure

Stepwise double excited-state proton transfer is not possible in 7-azaindole dimer

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.MB and NK would like to thank the support from the Deutscher Akademischer Austauschdienst (DAAD) and from the Deutsches Zentrum f¨ur Luft- und Raumfahrt (DLR) through the Thai- German mobility gran

Process planning and metallurgical issues for laser asisted spin froming of dual phase automotive steel

Postprint (published version

Understanding the disorder of the DNA base cytosine on the Au(111) surface

Using ultrahigh vacuum scanning tunneling microscopy (STM) and ab initio density functional theory, we have investigated in detail structures formed by cytosine on the Au(111) surface in clean ultrahigh vacuum conditions. In spite of the fact that the ground state of this DNA base on the surface is shown to be an ordered arrangement of cytosine one-dimensional branches (filaments), this structure has never been observed in our STM experiments. Instead, disordered structures are observed, which can be explained by only a few elementary structural motifs: filaments, five- and sixfold rings, which randomly interconnect with each other forming bent chains, T junctions, and nanocages. The latter may have trapped smaller structures inside. The formation of such an unusual assembly is explained by simple kinetic arguments as a liquid-glass transition. © 2008 American Institute of Physics

Thioredoxin and glutathione systems differ in parasitic and free-living platyhelminths

<p>Abstract</p> <p>Background</p> <p>The thioredoxin and/or glutathione pathways occur in all organisms. They provide electrons for deoxyribonucleotide synthesis, function as antioxidant defenses, in detoxification, Fe/S biogenesis and participate in a variety of cellular processes. In contrast to their mammalian hosts, platyhelminth (flatworm) parasites studied so far, lack conventional thioredoxin and glutathione systems. Instead, they possess a linked thioredoxin-glutathione system with the selenocysteine-containing enzyme thioredoxin glutathione reductase (TGR) as the single redox hub that controls the overall redox homeostasis. TGR has been recently validated as a drug target for schistosomiasis and new drug leads targeting TGR have recently been identified for these platyhelminth infections that affect more than 200 million people and for which a single drug is currently available. Little is known regarding the genomic structure of flatworm TGRs, the expression of TGR variants and whether the absence of conventional thioredoxin and glutathione systems is a signature of the entire platyhelminth phylum.</p> <p>Results</p> <p>We examine platyhelminth genomes and transcriptomes and find that all platyhelminth parasites (from classes Cestoda and Trematoda) conform to a biochemical scenario involving, exclusively, a selenium-dependent linked thioredoxin-glutathione system having TGR as a central redox hub. In contrast, the free-living platyhelminth <it>Schmidtea mediterranea </it>(Class Turbellaria) possesses conventional and linked thioredoxin and glutathione systems. We identify TGR variants in <it>Schistosoma </it>spp. derived from a single gene, and demonstrate their expression. We also provide experimental evidence that alternative initiation of transcription and alternative transcript processing contribute to the generation of TGR variants in platyhelminth parasites.</p> <p>Conclusions</p> <p>Our results indicate that thioredoxin and glutathione pathways differ in parasitic and free-living flatworms and that canonical enzymes were specifically lost in the parasitic lineage. Platyhelminth parasites possess a unique and simplified redox system for diverse essential processes, and thus TGR is an excellent drug target for platyhelminth infections. Inhibition of the central redox wire hub would lead to overall disruption of redox homeostasis and disable DNA synthesis.</p

Hanging Pictures or Searching the Web: Informing the Design of a Decision-Making System that Empowers Teachers to Appropriate Educational Resources to Their School’s Infrastructure

In this paper, we report work in designing a decision-making system that aims to support teachers in appropriating to their practice innovative scenarios that employ uses of information and communication technologies (ICT) in teaching and learning. To this end, we break down educational scenarios into micro-activities, and connect them to required and alternative infrastructure. We argue that micro-activities is a unit of analysis of educational scenarios that is compatible with the role of teachers as designers who select, decompose, combine, enact and revise different pieces of resources. This paper offers a reflective viewpoint on integrating ICT in existing scenarios and investigates how teaching objectives make use, or not, of the potential of digital technologies

The influence of using wet cellulose poultice on nanolime consolidation treatments applied on a limestone

Acknowledgments J.S. Pozo-Antonio was supported by the Ministry of Science and Innovation, Government of Spain through grant number RYC2020- 028902-I. J. Otero’s current research is funded by the European Commission on the Marie Skłodowska-Curie Actions (MSCA-IF) from the European Union’s Horizon 2020 on research and innovation, grant agreement N. 893762 (NANOMORT). Funding for open access charge was provided by Universidade de Vigo/CISUG.Consolidation treatment with nanolime is a common conservation intervention which needs more research to enhance penetration and mechanical properties while also minimizing the undesired white veil on the surface which significantly alters the surface appearance. In this light, the application of a cellulose poultice soaked in distilled water over the treated surface with nanolime tries to prevent the formation of white hazes and to favour nanolime carbonation and penetration in the pore structure. However, the real influence of this practice on the consolidation effectiveness has never been studied yet and is not yet well understood. In order to provide more insights about its most suitable application method, in this study, we investigated the effectiveness of a wet cellulose poultice for two different nanolime consolidation treatments on a weathered limestone. Nanolime has been synthetized by anion exchange processes and dispersed in two mediums: i) water and ii) 50% v/v of water and alcohol. The influence of the poultice on the penetration and aesthetic properties has been studied by drilling resistance measurement, ultrasounds test, stereomicroscopy, measurements of roughness and static contact angle, spectrophotometry and scanning electron microscopy (superficial and cross sectioned samples). Additionally, consolidation effectiveness has been evaluated through the changes in apparent density, open porosity, porosity network in the outer 5 mm of the surface by mercury intrusion porosimetry and surface cohesion by the peeling test. Results show that, contrary to what is usually assumed, samples where a wet cellulose poultice was applied after the consolidant reached the lowest penetration levels and retained lower dry matter in comparison to their counterparts without poultice. A consolidation treatment with nanolime is more complex that it is generally considered, and the application of poultices is not always enhancing consolidation level; the most suitable application procedure must be chosen with regards to the nanolime and substrate specific characteristics.Ministry of Science and Innovation, Government of Spain through grant number RYC2020- 028902-I.European Commission on the Marie Skłodowska-Curie Actions (MSCA-IF) from the European Union’s Horizon 2020 on research and innovation, grant agreement N. 893762 (NANOMORT)Funding for open access charge was provided by Universidade de Vigo/CISU