Phase transitions in simplified models with long-range interactions

We study the origin of phase transitions in some simplified models with long range interactions. For the ring model, we show that a possible new phase transition predicted in a recent paper by Nardini and Casetti from an energy landscape analysis does not occur. Instead of such phase transitions we observe a sharp, although without any non-analiticity, change from a core-halo to an only core configuration in the spatial distribution functions for low energies. By introducing a new class of solvable simplified models without any critical points in the potential energy, we show that a similar behaviour to the ring model is obtained, with a first order phase transition from an almost homogeneous high energy phase to a clustered phase, and the same core-halo to core configuration transition at lower energies. We discuss the origin of these features of the simplified models, and show that the first order phase transition comes from the maximization of the entropy of the system as a function of energy an an order parameter, as previously discussed by Kastner, which seems to be the main mechanism causing phase transitions in long-range interacting systems

Competição de cultivares de soja com plantas daninhas em Urutaí, GO.

Objetivou-se nesta pesquisa avaliar o potencial competitivo de cultivares de soja com plantas daninhas em duas épocas de semeadura nas condições edafoclimáticas de Urutaí, GO. O experimento foi conduzido em blocos ao acaso, com quatro repetições em parcelas subsubdivididas. Testou-se nas parcelas duas épocas de semeadura (novembro e dezembro), nas subparcelas as cultivares de soja (BRSGO Raíssa, BRSGO Amaralina, Emgopa 302 RR, BRSGO Indiara, BRS 7560, BRSGO Caiapônia, Pioneer P98Y11 e Pioneer P98C81) e nas subsubparcelas a convivência ou não de plantas daninhas com as cultivares. Quanto às plantas daninhas verificou-se maior ocorrência destas na soja semeada tardiamente. Houve efeito da convivência de plantas daninhas no rendimento de grãos e também interação significativa entre cultivares de soja e época de semeadura, mostrando que a interferência de plantas daninhas com a soja reduziu o rendimento de grãos, principalmente quando a semeadura das cultivares foi realizada em dezembro

Cultivares de soja: macrorregiões 3, 4 e 5 Goiás e Região Central do Brasil.

Grupo de maturidade relativa. Indicação de cultivares por região edafoclimática. Mancha olho-de-rã. Cancro da haste. Oídio. Nematóides de galhas. Manejo de mofo-branco em soja. Soja Louca II. Peso médio de sementes. Cultivares de soja convencional. Cultivares de soja transgênica (RR).bitstream/item/76085/1/catalogo-SojaGO-2012-FINAL.pdfCatálogo 02/2012

Seleção de linhagens de soja quanto a reação a ferrugem asiática, em diferentes momentos de inoculação.

Este ensaio teve o objetivo de selecionar linhagens de soja quanto a reação a ferrugem asiática, quando inoculadas no estádio vegetativo ou no estádio reprodutivo. Foram selecionadas 222 linhagens do programa de melhoramento da Embrapa Soja, consideradas com potencial para expressar resistência a ferrugem devido as fontes usadas nos cruzamentos que as originaram. Foram semeados dois vasos por linhagem, sendo um deixado em casa de vegetação infestada por Phakopsora pachyrhizi desde a semeadura e o outro só transferido para a casa infestada a partir do florescimento. Avaliou-se a severidade (% área foliar infectada), quantidade de esporulação (notas de 0 a 3) e tipo de lesão [RB (mais resistente), RT, TR ou Tan (mais suscetível)], no folíolo mais infectado de cada planta. Do grupo submetido ao fungo desde o vegetativo, 75 linhagens mostraram lesão RB, 29 RT, 25 TR e 93 Tan, e a esporulação predominante foi nota 1 para RB e RT, e nota 2 para TR e Tan. Do grupo submetido ao fungo a partir do florescimento, foram 58 RB, 49 RT, 25 TR e 90 Tan, e a esporulação predominante foi nota 1 para RB, nota 2 para RT e TR, e nota 3 para Tan. Os resultados mostraram que nas linhagens com lesões Tan e TR, o momento da exposição das plantas ao fungo não interferiu na reação a doença. As linhagens com lesões RB e RT, expostas ao fungo a partir da floração, em geral apresentaram maior esporulação, menor número de lesões RB, maior número de lesões RT e maior severidade média. Verificou-se que, apesar da alta virulência do fungo, existem linhagens promissoras para se tornarem cultivares resistentes

Association of coronary calcification with prognosis of Covid-19 patients without known heart disease

Risk factors that determine the severity of Covid-19 have not been fully elucidated. The aim of this study was to evaluate the role of coronary artery calcification (CAC) as a risk factor for death or mechanical ventilation (MV) of patients without known heart disease infected with Covid-19. We analyzed 283 consecutive in-patients with acute respiratory symptoms with chest computed tomography (chest-CT), without previous heart disease, and criteria for Covid-19 (RT-PCR positive and/or typical clinical and chest-CT findings). CAC was classified by the number of coronary segments affected as absent (0), mild (1-3), and severe calcification (more than 3). The association between CAC, CAC severity, and death or MV due to severe respiratory failure was assessed by logistic regression. The mean age was 58.7 +/- 15.7 years and 54.1% were men. Patients with CAC were older, more likely to have hypertension, and less likely to be obese. CAC was present in 75 patients (26.5%), of which 42 had a mild calcification and 33 had severe calcification, and was associated with death (OR=2.35, 95%CI: 1.01-5.48) or MV (OR=2.72, 95%CI: 1.20-6.20) adjusted for multiple confounders, with significant and increased odds ratio for the severe form of CAC (death: OR=3.70, 95%CI: 1.20-11.42; MV: OR=3.30, 95%CI: 1.09-9.95). We concluded that CAC was an independent risk factor for death or MV in Covid-19 patients without previous heart disease, particularly for those with severe calcification. CAC can be easily visualized on common chest-CT, widely used in evaluation of moderate to severe Covid-19

The impact of polymorphic variations in the 5p15, 6p12, 6p21 and 15q25 loci on the risk and prognosis of Portuguese patients with non-small cell lung cancer

Polymorphic variants in the 5p15, 6p12, 6p21, and 15q25 loci were demonstrated to potentially contribute to lung cancer carcinogenesis. Therefore, this study was performed to assess the role of those variants in non-small cell lung cancer (NSCLC) risk and prognosis in a Portuguese population. MATERIALS AND METHODS: Blood from patients with NSCLC was prospectively collected. To perform an association study, DNA from these patients and healthy controls were genotyped for a panel of 19 SNPs using a Sequenom® MassARRAY platform. Kaplan-Meier curves were used to assess the overall survival (OS) and progression-free survival (PFS). RESULTS: One hundred and forty-four patients with NSCLC were successfully consecutively genotyped for the 19 SNPs. One SNP was associated with NSCLC risk: rs9295740 G/A. Two SNPs were associated with non-squamous histology: rs3024994 (VEGF intron 2) T/C and rs401681 C/T. Three SNPs were associated with response rate: rs3025035 (VEGF intron 7) C/T, rs833061 (VEGF -460) C/T and rs9295740 G/A. One SNP demonstrated an influence on PFS: rs401681 C/T at 5p15, p?=?0.021. Four SNPs demonstrated an influence on OS: rs2010963 (VEGF +405 G/C), p?=?0.042; rs3025010 (VEGF intron 5 C/T), p?=?0.047; rs401681 C/T at 5p15, p?=?0.046; and rs31489 C/A at 5p15, p?=?0.029. CONCLUSIONS: Our study suggests that SNPs in the 6p12, 6p21, and 5p15 loci may serve as risk, predictive and prognostic NSCLC biomarkers. In the future, SNPs identified in the genomes of patients may improve NSCLC screening strategies and therapeutic management as well.This project was supported by Programa Doutoral em Medicina e Oncologia Molecular, University of Porto, Porto, Portugal and University of Minho, Braga, Portugal. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript