Meteorite cloudy zone formation as a quantitative indicator of paleomagnetic field intensities and cooling rates on planetesimals

Metallic microstructures in slowly-cooled iron-rich meteorites reflect the thermal and magnetic histories of their parent planetesimals. Of particular interest is the cloudy zone, a nanoscale intergrowth of Ni-rich islands within a Ni-poor matrix that forms below 350{\deg}C by spinodal decomposition. The sizes of the islands have long been recognized as reflecting the low-temperature cooling rates of meteorite parent bodies. However, a model capable of providing quantitative cooling rate estimates from island sizes has been lacking. Moreover, these islands are also capable of preserving a record of the ambient magnetic field as they grew, but some of the key physical parameters required for recovering reliable paleointensity estimates from magnetic measurements of these islands have been poorly constrained. To address both of these issues, we present a numerical model of the structural and compositional evolution of the cloudy zone as a function of cooling rate and local composition. Our model produces island sizes that are consistent with present-day measured sizes. This model enables a substantial improvement in the calibration of paleointensity estimates and associated uncertainties. In particular, we can now accurately quantify the statistical uncertainty associated with the finite number of islands and the uncertainty on their size at the time of the record. We use this new understanding to revisit paleointensities from previous pioneering paleomagnetic studies of cloudy zones. We show that these could have been overestimated but nevertheless still require substantial magnetic fields to have been present on their parent bodies. Our model also allows us to estimate absolute cooling rates for meteorites that cooled slower than 10000{\deg}C My-1. We demonstrate how these cooling rate estimates can uniquely constrain the low-temperature thermal history of meteorite parent bodies.Comment: Manuscript resubmitted after revision

Asymptotically safe extensions of the Standard Model with flavour phenomenology

We investigate asymptotically safe extensions of the Standard Model with new matter fields arising in the TeV energy range. The new sector contains singlet scalars and vector-like fermions in representations which permit Yukawa interactions with the Standard Model leptons. Phenomenological implications are explored including charged lepton flavour violation, Drell-Yan processes and lepton anomalous magnetic moments. For the latter, we find that BSM contributions can be sizeable enough to explain the present experimental discrepancies of the electron and muon anomalous magnetic moments with the Standard Model.Comment: 4 pages, 4 figures. Contribution to the 2019 EW session of the 54th Rencontres de Morion

Depletion of mitochondria in mammalian cells through enforced mitophagy

Mitochondria are not only the 'powerhouse' of the cell; they are also involved in a multitude of processes that include calcium storage, the cell cycle and cell death. Traditional means of investigating mitochondrial importance in a given cellular process have centered upon depletion of mtDNA through chemical or genetic means. Although these methods severely disrupt the mitochondrial electron transport chain, mtDNA-depleted cells still maintain mitochondria and many mitochondrial functions. Here we describe a straightforward protocol to generate mammalian cell populations with low to nondetectable levels of mitochondria. Ectopic expression of the ubiquitin E3 ligase Parkin, combined with short-term mitochondrial uncoupler treatment, stimulates widespread mitophagy and effectively eliminates mitochondria. In this protocol, we explain how to generate Parkin-expressing, mitochondria-depleted cells from scratch in 23 d, as well as offer a variety of methods for confirming mitochondrial clearance. Furthermore, we describe culture conditions to maintain mitochondrial-depleted cells for up to 30 d with minimal loss of viability, for longitudinal studies. This method should prove useful for investigating the importance of mitochondria in a variety of biological processes

A critical analysis of Peru's HIV grant proposals to the Global Fund.

Peru has applied to six of the Global Fund to Fight AIDS, Tuberculosis and Malaria (the Global Fund) rounds for funding, achieving success on four occasions. The process of proposal development has, however, been criticised, especially concerning the use of evidence, relevance/consistency and performance indicators. We aimed to analyse the Peruvian Global Fund proposals according to those dimensions, providing feedback to improve future local efforts and inform global discussions around Global Fund procedures. We analysed the content of four HIV-focused proposals (rounds 2, 5, 6 and 8) regarding epidemic context, needs identification and prioritisation and monitoring and evaluation systems. Peruvian proposals submitted after round 1 were described as resulting from collaborative inputs involving formerly unrepresented sectors, principally 'vulnerable populations'. However, difficulties arose regarding the amount and quality of evidence about the epidemiological context; limited consideration of social determinants of the epidemic; lack of theory-driven interventions, and little synergy across projects and the inclusion of weak monitoring and evaluation systems, with poor indicators and measurement procedures. Prioritising the development of analytical and technical skills to generate Global Fund proposals would enhance the country's capacity to produce and utilise evidence, improve the technical-political interface, strengthen information systems and lead to more informed decision making and accountability

“Entrelugares” identificados numa experiência de intercâmbio universitário na Itália

No âmbito do projeto de pesquisa “Elaboração de subsídios teórico-metodológicos para a educação intercultural”, a bolsista IC, estudante de pedagogia (UFSC), realizou um estágio de intercâmbio acadêmico na Universidade italiana Roma Tre e no projeto Aquilone, durante o primeiro semestre de 2007. Buscou compreender o caráter multidimensional e complexo de experiências educativas realizadas na interação entre sujeitos e movimentos sociais de identidades culturais diferentes, de modo a colaborar para a elaboração de referenciais teórico-metodológicos para a Educação Intercultural. A atuação no espaço “inter”, no “entrelugar” entre duas ou mais culturas, particularmente em processos migratórios, permitiu identificar a diferença de enfoque da educação intercultural, entre os países do norte e do sul; a sua eminente importância como mediadora das relações dos imigrantes com os autóctones; a importância da utilização de processos de trocas culturais, interculturais para a desesteriotipização, descolonização cultural e (des)subalternização

First documented record of a living solemyid bivalve in a pockmark of the Nile Deep-sea Fan (eastern Mediterranean Sea)

A living specimen of a solemyid bivalve was collected at bathyal depths near a pockmark in the Nile Deep-sea Fan (eastern Mediterranean) and is here presented. Both taxonomic and molecular results suggest a Solemya species but due to the small size of the animal and the lack of molecular data for other solemyid species the species cannot be determined. This is the first record of a living solemyid from deep-sea cold seeps in the Mediterranean Basin.FCT - SFRH/ BPD/64154/2009ANR DEEP-OASES - ANRO6BDV005CHEMECO ESF EURODEEPMPG-CNRS-GDRE - DIWOO

Desconstrução de Subalternidades e Idéias Anarquistas: possíveis convergências à caminho da insubordinação

A pesquisa em desenvolvimento nasceu dentro do projeto “Educação Intercultural: desconstrução de subalternidades em práticas educativas e socioculturais”. Surge da busca por aprofundar a perspectiva da desconstrução de subalternidades relacionando-a com movimentos políticos/sociais de insubordinação. O objetivo é discutir as possíveis convergências entre a opção pela desconstrução de subalternidades e as idéias anarquistas. Parte da desconstrução de subalternidades, enquanto uma perspectiva que leva em conta a complexidade do mundo atual, não acredita ser detentora de uma verdade redentora (Azibeiro) e busca a identificação de entre-lugares viáveis ao dialogo a construção do pensamento fronteiriço. É realizada por meio de pesquisa bibliográfica, análise e identificação dos pressupostos teóricos confluentes. Traz em conta os aportes da desconstrução de subalternidades: colonialidade do poder, eurocentrismo (Quijano), colonialidade-modernidade, diferença colonial, consciência dupla, pensamento fronteiriço (Mignolo) transmodernidade (Dussel), Entre-Lugar (Bhabha). Busca-se: levantar um pouco da história das idéias e movimentos anarquistas (Woodcock); traçar convergências como, por exemplo, a defesa pela desconstrução enquanto um postulado à transformação, à construção (Bakunin); refletir sobre o movimento antiglobalização (Liberato e Klein), sua relação com o surgimento de uma nova utopia, suas possíveis confluências ao manter um viés libertário, uma rebeldia visceral contra toda e qualquer forma de opressão e a autonomia como caminho e fim contribuindo com um horizonte de transformação social

Backaction in metasurface etalons

We consider the response of etalons created by a combination of a conventional mirror and a metasurface, composed of a periodic lattice of metal scatterers with a resonant response. This geometry has been used previously for perfect absorption, in so-called Salisbury screens, and for hybridization of localized plasmons with Fabry-Perot resonances. The particular aspect we address is if one can assume an environment-independent reflectivity for the metasurface when calculating the reflectivity of the composite system, as in a standard Fabry-Perot analysis, or whether the fact that the metasurface interacts with its own mirror image renormalizes its response. Using lattice sum theory, we take into account all possible retarded dipole-dipole interactions of scatterers in the metasurface amongst each other, and through the mirror. We show that while a layer-by-layer Fabry-Perot formalism captures the main qualitative features of metasurface etalons, in fact the mirror modifies both the polarizability and reflectivity of the metasurface in a fashion that is akin to Drexhage's modification of the radiative properties of a single dipole.Comment: 10 pages, 5 figure