Fractal Conductance Fluctuations of Classical Origin

In mesoscopic systems conductance fluctuations are a sensitive probe of electron dynamics and chaotic phenomena. We show that the conductance of a purely classical chaotic system with either fully chaotic or mixed phase space generically exhibits fractal conductance fluctuations unrelated to quantum interference. This might explain the unexpected dependence of the fractal dimension of the conductance curves on the (quantum) phase breaking length observed in experiments on semiconductor quantum dots.Comment: 5 pages, 4 figures, to appear in PR

Some Remarks about Variable Mass Systems

We comment about the general argument given to obtain the rocket equation as it is exposed in standard textbooks. In our opinion, it can induce students to a wrong answer when solving variable mass problems.Comment: 2 page

Comportamento populacional de cupiúba (Goupia glabra Aubl.) em floresta de terra firme na fazenda Rio Capim, Paragominas (PA).

Goupia glabra Aublet, popularmente conhecida como cupiúba, é uma espécie arbórea da família Celastraceae. Possui árvores de grande porte, podendo muitas vezes ocupar a posição de dossel superior em florestas primárias. É uma espécie de grande importância econômica para a região onde ocorre e para o país, sendo comercializada, inclusive, no mercado internacional, devido seus diversos usos e características peculiares. O presente estudo cruza conhecimentos de botânica, ecologia e importância comercial da espécie com informações do comportamento estrutural da cupiúba, a fim de facilitar ações de bom manejo silvicultural, inclusive juntamente com outras espécies que compõe a comunidade na área estudada e na região. Em 84 ha de floresta natural densa de terra firme, na Fazenda Rio Capim, de propriedade da Cikel Brasil Verde S. A., no município de Paragominas (PA), Goupia glabra foi uma das espécies mais representativas quanto ao seu grupo na estrutura florestal, sendo de grande importância ecológica naquela área. Considerando as árvores com diâmetro acima de 45 cm, a espécie apresenta abundância de 0,81 árvore/ha, freqüência de 100%, com área basal de 0,41 m2/ha, volume de 2,58 m3/ha, distribuição diamétrica em todas as classes de árvores, de 45 cm até 144 cm, e qualidade de fuste bem representativa para comercialização.Publicado também on-line

Smartphone apps for the self-management of low back pain: A systematic review

Guidelines for low back pain (LBP) often recommend the use of self-management such as unsupervised exercise, booklets, and online education. Another potentially useful way for patients to self-manage LBP is by using smartphone applications (apps). However, to date, there has been no rigorous evaluation of LBP apps and no guidance for consumers on how to select high-quality, evidence-based apps. This chapter reviews smartphone apps for the self-management of LBP and evaluates their content quality and whether they recommend evidence-based interventions. This chapter shows that generally app developers are selecting interventions that are endorsed by guidelines, although their quality is low. There are many apps available for the self-management of LBP, but their effectiveness in improving patient outcomes has not been rigorously assessed. App developers need to work closely with healthcare professionals, researchers, and patients to ensure app content is accurate, evidence based, and engaging

Catalogação do banco de dados do melhoramento de feijoeiro comum da Embrapa.

O objetivo deste trabalho foi recuperar arquivos de dados, a fim de reunir, uniformizar, armazenar, indexar e disponibilizar as informações técnicas de interesse para as atividades de pesquisa

Systemic model for diagnosis of the micro, small and medium enterprises from two cities from the countryside of the state of São Paulo in Brazil

This article presents a proposal of a systemic model composed for the micro and small companies (MSE) of the region of Ribeirão Preto and the agents which influenced their environment. The proposed model was based on Stafford Beer's (Diagnosing the system for organizations. Chichester, Wiley, 1985) systemic methodologies VSM (Viable System Model) and on Werner Ulrich's (1983) CSH (Critical Systems Heuristics). The VSM is a model for the diagnosis of the structure of an organization and of its flows of information through the application of the cybernetics concepts (Narvarte, In El Modelo del Sistema Viable-MSV: experiencias de su aplicación en Chile. Proyecto Cerebro Colectivo del IAS, Santiago, 2001). On the other hand, CSH focus on the context of the social group applied to the systemic vision as a counterpoint to the organizational management view considered by the VSM. MSE of Ribeirão Preto and Sertãozinho had been analyzed as organizations inserted in systems that relate and integrate with other systems concerning the public administration, entities of representation and promotion agencies. The research questions: which are the bonds of interaction among the subsystems in this process and who are the agents involved? The systemic approach not only diagnosed a social group, formed by MSE of Ribeirão Preto and Sertãozinho, public authorities and support entities, but could also delineate answers that aimed the clarification of obscure questions generating financial assistance to the formularization of efficient actions for the development of this system. © 2009 Springer Science+Business Media, LLC

Palliative splenic irradiation for symptomatic splenomegaly in non-Hodgkin lymphoma

INTRODUCTION AND AIMS: Splenic marginal zone lymphoma, an uncommon subtype of non-Hodgkin lymphoma (NHL), is usually present with symptomatic splenomegaly. Although splenectomy has long been considered the first-line therapy in symptomatic or cytopenic patients, it can lead to significant morbidity and mortality. Splenic irradiation is an option for patients who have a poor response to systemic therapy and/or are not surgical candidates. In this paper, we present a case report of a patient who received splenic radiotherapy for symptomatic splenomegaly. METHODS: An 85-year-old Caucasian man with a 4 year history of low-grade NHL presented with progressive pancytopenia, significant weight loss and symptomatic splenomegaly (abdominal discomfort, sense of fullness and limitation of mobility due to spleen size). The patient refused splenectomy and, in December 2017, was referred to palliative splenic radiotherapy. He was initially treated with five fractions of one Grey (Gy) in order to evaluate clinical and haematology response. After that, 1.5 Gy daily, 5 days a week for 3 weeks. 3D conformal radiotherapy, multiple fields and mixed energy (6 and 15 Mv) were used. RESULTS: Radiotherapy allowed significant splenic reduction to almost half the size, resolving abdominal discomfort and improving quality of life. There was no decline of haemoglobin, leukocytes and platelet counts; in fact, there was a marginal increase. CONCLUSION: Palliative splenic irradiation was well tolerated confirming that it is a safe treatment option for palliation of symptomatic splenomegaly. Thereby, splenic irradiation should be strongly considered in the management of symptomatic splenomegaly, for selected patients who are refractory to or unsuitable for other options or when the patient refuses other treatments.info:eu-repo/semantics/publishedVersio

Longevity, body dimension and reproductive mode drive differences in aquatic versus terrestrial life-history strategies

1. Aquatic and terrestrial environments display stark differences in key environmental factors and phylogenetic composition but their consequences for the evolution of species' life-history strategies remain poorly understood. 2. Here, we examine whether and how life-history strategies vary between terrestrial and aquatic species. We use demographic information for 685 terrestrial and 122 aquatic animal and plant species to estimate key life-history traits. We then use phylogenetically corrected least squares regression to explore potential differences in trade-offs between life-history traits between both environments. We contrast life-history strategies of aquatic versus terrestrial species in a principal component analysis while accounting for body dimensions and phylogenetic relationships. 3. Our results show that the same trade-offs structure terrestrial and aquatic life histories, resulting in two dominant axes of variation that describe species' pace of life and reproductive strategies. Terrestrial plants display a large diversity of strategies, including the longest-lived species in this study. Aquatic animals exhibit higher reproductive frequency than terrestrial animals. When correcting for body size, mobile and sessile terrestrial organisms show slower paces of life than aquatic ones. 4. Aquatic and terrestrial species are ruled by the same life-history trade-offs, but have evolved different strategies, likely due to distinct environmental selective pressures. Such contrasting life-history strategies have important consequences for the conservation and management of aquatic and terrestrial species

Fe/Co Alloys for the Catalytic Chemical Vapor Deposition Synthesis of Single- and Double-Walled Carbon Nanotubes (CNTs). 1. The CNT−Fe/Co−MgO System

Mg0.90FexCoyO (x + y ) 0.1) solid solutions were synthesized by the ureic combustion route. Upon reduction at 1000 °C in H2-CH4 of these powders, Fe/Co alloy nanoparticles are formed, which are involved in the formation of carbon nanotubes, which are mostly single and double walled, with an average diameter close to 2.5 nm. Characterizations of the materials are performed using 57Fe Mo¨ssbauer spectroscopy and electron microscopy, and a well-established macroscopic method, based on specific-surface-area measurements, was applied to quantify the carbon quality and the nanotubes quantity. A detailed investigation of the Fe/Co alloys’ formation and composition is reported. An increasing fraction of Co2+ ions hinders the dissolution of iron in the MgO lattice and favors the formation of MgFe2O4-like particles in the oxide powders. Upon reduction, these particles form R-Fe/Co particles with a size and composition (close to Fe0.50Co0.50) adequate for the increased production of carbon nanotubes. However, larger particles are also produced resulting in the formation of undesirable carbon species. The highest CNT quantity and carbon quality are eventually obtained upon reduction of the iron-free Mg0.90Co0.10O solid solution, in the absence of clusters of metal ions in the starting material. Introduction Catalyti