Statistical model for the effects of phase and momentum randomization on electron transport

A simple statistical model for the effects of dephasing on electron transport in one-dimensional quantum systems is introduced, which allows to adjust the degree of phase and momentum randomization independently. Hence, the model is able to describe the transport in an intermediate regime between classic and quantum transport. The model is based on B\"uttiker's approach using fictitious reservoirs for the dephasing effects. However, in contrast to other models, at the fictitious reservoirs complete phase randomization is assumed, which effectively divides the system into smaller coherent subsystems, and an ensemble average over randomly distributed dephasing reservoirs is calculated. This approach reduces not only the computation time but allows also to gain new insight into system properties. In this way, after deriving an efficient formula for the disorder-averaged resistance of a tight-binding chain, it is shown that the dephasing-driven transition from localized-exponentially to ohmic-linear behavior is not affected by the degree of momentum randomizing dephasing.Comment: 6 pages, 7 figure

Recurrent Highway Networks

Many sequential processing tasks require complex nonlinear transition functions from one step to the next. However, recurrent neural networks with 'deep' transition functions remain difficult to train, even when using Long Short-Term Memory (LSTM) networks. We introduce a novel theoretical analysis of recurrent networks based on Gersgorin's circle theorem that illuminates several modeling and optimization issues and improves our understanding of the LSTM cell. Based on this analysis we propose Recurrent Highway Networks, which extend the LSTM architecture to allow step-to-step transition depths larger than one. Several language modeling experiments demonstrate that the proposed architecture results in powerful and efficient models. On the Penn Treebank corpus, solely increasing the transition depth from 1 to 10 improves word-level perplexity from 90.6 to 65.4 using the same number of parameters. On the larger Wikipedia datasets for character prediction (text8 and enwik8), RHNs outperform all previous results and achieve an entropy of 1.27 bits per character.Comment: 12 pages, 6 figures, 3 table

Nutrition-Sensitive Agriculture Interventions in Mountain Areas-Lessons Learned From a 5-Country Project to Upscale Best Practices

Many people living in mountain regions in lowand middle-income countries are vulnerable to food and nutrition insecurity, which contributes to poor nutritional status. Food and nutrition security require stability of access to affordable, safe, diverse, and nutritious foods. In mountainous areas, affordability and access to diverse foods are challenged by climatic factors constraining agricultural production, poor infrastructure, and geographic isolation. This article describes a nutrition-sensitive agriculture (NSA) project focusing on 5 countries—Ethiopia, Kyrgyzstan, Nepal, Pakistan, and Peru— where 132 microinterventions were implemented by rural service providers (RSPs) who received training and technical support from the project. These microinterventions serve as learning cases for advocacy work to promote the NSA approach at the local, national, and global levels. They are also documented on an Internet platform allowing RSPs and other stakeholders to share best practices and lessons learned at the national and global levels. Preliminary results indicate that this approach is highly effective in addressing nutrition and livelihood issues in remote mountain areas. To scale up the approach and boost its integration into policies at the local, national, and global levels, 2 aspects will be critical. First, more systemic and integrated NSA initiatives need to be implemented that functionally combine production- and consumption-related aspects to effectively change nutrition behavior and serve as learning cases for scaling up. Second, effective capacity development of RSPs and encouragement of interaction among them is key to empowering them as change agents

A história encenada em Os Sertões de Euclides da Cunha

A história encenada em Os Sertões de Euclides da Cunh

O TRADUTOR IMPLÍCITO. CONSIDERAÇÕES ACERCA DA TRANSLINGUIDADE DE OS SERTÕES

O TRADUTOR IMPLÍCITO. CONSIDERAÇÕES ACERCA DA TRANSLINGUIDADE DE OS SERTÕE

Electronic conduction in linear quantum systems: Coherent transport and the effects of decoherence

Coherent quantum transport in linear and quasi-linear tight-binding models and the influence of decoherence are studied. For the coherent transport description, Green functions and surface Green functions of semi-infinite systems are calculated and the transmission through defects and finite tight-binding chains with and without diagonal disorder are examined. A statistical model based on the division of a large system into coherent subsystems and decoherence regions is analyzed. While on the total system level, classical rate equations interrelate electron energy distribution functions assigned to the decoherence regions, the transition rates themselves are calculated using quantum transport formalism. Thus a two-scale approach is used. For contact Fermi energies within the tight-binding band of the system without disorder, ohmic large scale behavior is observed for any finite density of decoherence regions. If the Fermi energy is outside the band, and for disordered systems, critical decoherence densities are defined. Above the critical densities, material-specific resistivities can be defined. Applying the statistical model for the effects of decoherence on DNA double strands, experimental findings for base-sequence dependent conductance are reproduced

CONVIVENDO COM OS SERTÕES – EXPERIÊNCIAS E REFLEXÕES DE UM ESTUDIOSO ALEMÃO

O autor da presente palestra relembra e contextualiza seu interesse e fascínio, a partir do final dos anos 1960, por Os Sertões de Euclides da Cunha, livro que lê, na perspectiva da dialética do Esclarecimento, como relato parcialmente ambíguo ou contraditório de um patriota que, imbuído de ideias do progresso civilizatório, pretende pesquisar e expressar a totalidade das causas, características, aspectos objetivos e subjetivos de um crime cometido em nome da nação e da civilização: a guerra de Canudos. A complexidade e enigmaticidade da tarefa leva Euclides a criar um ensaio interdisciplinar, fundindo abordagens científicas, antropológicas e poéticas numa retórica erudita, de forte impacto emocional e apelo humanitário. Tudo isto motivou o palestrante a traduzir Os Sertões ao alemão, obrigando-o a amplas pesquisas e minuciosas análises de texto, das quais são apresentados exemplos. A palestra finaliza com vozes sobre a repercussão de Krieg im Sertão nos países de língua alemã.The author of this lecture recalls and contextualizes his interest and fascination, from the end of the 1960s, on Os Sertões by Euclides da Cunha, a book that he reads, from the perspective of the dialectic of Enlightenment, as an account, partially ambiguous or contradictory, of a patriot who, imbued with ideas of civilizing progress, intends to research and express the totality of the causes, characteristics, objective and subjective aspects of a crime committed in the name of the Nation and Civilization: the War of Canudos. The complexity and enigmatic nature of the task led Euclides to create an interdisciplinary essay, merging scientific, anthropological and poetic approaches into erudite rhetoric, with a strong emotional impact and humanitarian appeal. All this motivated the speaker to translate Os Sertões into German, obliging him to carry out extensive research and meticulous text analyses, of which examples are presented. The lecture ends with voices about the repercussion of Krieg im Sertão in German-speaking countries