A Real Space Description of Magnetic Field Induced Melting in the Charge Ordered Manganites: I. The Clean Limit

We study the melting of charge order in the half doped manganites using a model that incorporates double exchange, antiferromagnetic superexchange, and Jahn-Teller coupling between electrons and phonons. We primarily use a real space Monte Carlo technique to study the phase diagram in terms of applied field $(h)$ and temperature $(T)$, exploring the melting of charge order with increasing $h$ and its recovery on decreasing $h$. We observe hysteresis in this response, and discover that the `field melted' high conductance state can be spatially inhomogeneous even without extrinsic disorder. The hysteretic response plays out in the background of field driven equilibrium phase separation. Our results, exploring $h$, $T$, and the electronic parameter space, are backed up by analysis of simpler limiting cases and a Landau framework for the field response. This paper focuses on our results in the `clean' systems, a companion paper studies the effect of cation disorder on the melting phenomena.Comment: 16 pages, pdflatex, 11 png fig

Dietas naturais na criação de Chrysomya albiceps (Wiedemann, 1819; Diptera: Calliphoridae): estudo comparado Natural diets to rear Chrysomya albiceps (Wiedemann, 1819; Diptera: Calliphoridae): a comparative study

Procurou-se observar o desenvolvimento pós-embrionário de Chrysomya albiceps, testando-se, comparativamente, dietas à base de sardinha e carne eqüina. Os substratos frescos foram previamente mantidos a 30&deg;C de temperatura durante duas horas. Foram inoculadas 50 neolarvas em 100g de dieta por repetição. Utilizaram-se quatro repetições por tratamento. O experimento foi conduzido em condições de laboratório. O peso médio das larvas após o abandono espontâneo das dietas foi de 91,19mg, no substrato à base de carne eqüina e 76,01mg, no substrato à base de sardinha, a diferença foi, portanto, significativa. A taxa de sobrevivência larval registrada foi superior a 80%, enquanto a taxa de sobrevivência pupal foi próxima a 100%. A razão sexual foi próxima a 0,5. A dieta à base de carne eqüina mostrou-se mais adequada ao desenvolvimento de C. albiceps, pois as larvas mantidas neste substrato apresentaram-se mais pesadas, o que potencializa a capacidade reprodutiva do adulto.<br>The objective of the present study was to observe the postembryonic development of Chrysomya albiceps reared on sardines or horse meat and to compare the results. Fresh substratos were maintened m an oven ai 30&deg;C for 2 hours. Fifty newly emerged larvas were inoculated into 100g diel per reptication. Four replications per treatment were used. The experiment was conducted under laboratory conditions. The mean weight of postfeeding larvas was 91.19mg for especimens reared on horse meat and 76.01mg for especimens reared on sardines, with a marked difference between diets. Larval viability was more than 80% for the two diets, while pupal viability was dose to 100%. The sex ratio was about 0.5. The horse meat diet proved to be more adequate for the development of C. albiceps since the larvas weighed more, with consequent potentiations of adult reproductive abilily

New directions in EU foreign policy governance: cross-loading, leadership and informal groupings

This article explores new patterns of interaction in foreign affairs among European Union (EU) Member States post-Lisbon, which have increased reliance on horizontal and informal practices. It argues that cross-loading among Member States outside EU institutions has moved centre stage and contributed to smaller groups of like-minded Member States working together. This shift challenges much of our understanding of Europeanization, which is based on vertical forms of uploading and downloading. We illustrate these dynamics using the case of Sweden's recognition of Palestine in October 2014. While this seemed to break away from the established EU consensus, Sweden's decision aimed at leading the way and imparting momentum, especially within the like-minded group of EU countries. Rather than being an example of de-Europeanization, this case shows how Member States can seek new ways of exerting influence in the post-Lisbon environment

Associação entre larvas de Chrysomya megacephala (Fabricius) e Chrysomya albiceps (Wiedemann), Chrysomya megacephala (Fabricius) e Cochliomyia macellaria (Fabricius) (Calliphoridae, Diptera) sob condições de laboratório Association between Chrysomya megacephala (Fabricius) and Chrysomya albiceps (Wiedemann), Chrysomya megacephala (Fabricius) and Cochliomyia macellaria (Fabricius) larvae (Calliphoridae, Diptera), under laboratory conditions

<abstract language="eng">This paper intends to recognize some aspects of interspecific relationships between Chrysomya megacephala (Fabricius) and C. albiceps (Wiedemann) and between C. megacephala and Cochliomyia macellaria (Fabricius) larvae in laboratory. A diet consisting of decomposing horse flesh was used, and the relation of 1 larva/g diet was established. The development of the two species was done in pure and associated cultures. The association with Chrysomya albiceps influenced the post-embrionary development period and the weight of mature larvae of the C. megacephala, reducing their. Such weight decrease, along with the predation of larvae of C. megacephala larvae, yelded a decrease in survival in all of the stages. Larvae of this species showed an increase in its weight when associated with Cochliomyia macellaria. The native species responded to the association by reducing its body weigth and its viability. This association doesnt influence the duration of post-embrionary development

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora