206 research outputs found

    Static and dynamic properties of vortices in anisotropic magnetic disks

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    We investigate the effect of the magnetic anisotropy (KzK_z) on the static and dynamic properties of magnetic vortices in small disks. Our micromagnetic calculations reveal that for a range of KzK_z there is an enlargement of the vortex core. We analyze the influence of KzK_z on the dynamics of the vortex core magnetization reversal under the excitation of a pulsed field. The presence of KzK_z, which leads to better resolved vortex structures, allows us to discuss in more details the role played by the in-plane and perpendicular components of the gyrotropic field during the vortex-antivortex nucleation and annihilation.Comment: 4 pages, 4 figure

    Deep Sequencing Analysis of RNAs from Citrus Plants Grown in a Citrus Sudden Death-Affected Area Reveals Diverse Known and Putative Novel Viruses.

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    Citrus sudden death (CSD) has caused the death of approximately four million orange trees in a very important citrus region in Brazil. Although its etiology is still not completely clear, symptoms and distribution of affected plants indicate a viral disease. In a search for viruses associated with CSD, we have performed a comparative high-throughput sequencing analysis of the transcriptome and small RNAs from CSD-symptomatic and -asymptomatic plants using the Illumina platform. The data revealed mixed infections that included Citrus tristeza virus (CTV) as the most predominant virus, followed by the Citrus sudden death-associated virus (CSDaV), Citrus endogenous pararetrovirus (CitPRV) and two putative novel viruses tentatively named Citrus jingmen-like virus (CJLV), and Citrus virga-like virus (CVLV). The deep sequencing analyses were sensitive enough to differentiate two genotypes of both viruses previously associated with CSD-affected plants: CTV and CSDaV. Our data also showed a putative association of the CSD-symptomatic plants with a specific CSDaV genotype and a likely association with CitPRV as well, whereas the two putative novel viruses showed to be more associated with CSD-asymptomatic plants. This is the first high-throughput sequencing-based study of the viral sequences present in CSD-affected citrus plants, and generated valuable information for further CSD studies

    Shear behaviour of rammed earth walls repaired by means of grouting

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    Southern Portugal presents a rich heritage constituted by several constructions made from unstabilised rammed earth (URE), which are threatened by several factors, ranging from lack of conservation to a non-negligible seismic hazard. These threatens are enhanced by the fact that little is known about the shear behaviour of URE constructions. The preservation of this heritage requires definitely the development of this knowledge and, in addition, the development of adequate intervention solutions. This paper presents an experimental program where the shear behaviour of URE is assessed by means of diagonal compression tests on representative wallet-specimens. Furthermore, the use of mud grouts in repairing cracks was also assessed. The results showed that the shear behaviour of URE depends on the binding capacity promoted by the clay fraction and on the friction and interlocking promoted by the coarse aggregates. The repair by injection was shown to promote satisfactory shear strength recovery of the specimens, but was less effective in recovering the initial shear stiffness.Fundação para a Ciência e a Tecnologia (FCT

    so much work, so many lost opportunities

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    Mainoli, B., Machado, T., Duarte, G. S., Prada, L., Gonçalves, N., Ferreira, J. J., & Costa, J. (2021). Analysis of clinical and methodological characteristics of early COVID-19 treatment clinical trials: so much work, so many lost opportunities. BMC Medical Research Methodology, 21(1), 1-10. [42]. https://doi.org/10.1186/s12874-021-01233-wBackground: The COVID-19 pandemic continues to rage on, and clinical research has been promoted worldwide. We aimed to assess the clinical and methodological characteristics of treatment clinical trials that have been set forth as an early response to the COVID-19 pandemic. Methods: First, we reviewed all registered clinical trials on COVID-19. The World Health Organization International Trials Registry Platform and national trial registries were searched for COVID-19 trials through April 19th, 2020. For each record, independent researchers extracted interventions, participants, and methodological characteristics. Second, on September 14th, 2020 we evaluated the recruitment status and availability of the results of COVID-19 treatment trials previously identified. Results: In April 2020, a total of 580 trials evaluating COVID-19 treatment were registered. Reporting quality was poor (core participant information was missing in 24.1 to 92.7%). Between 54.0 and 93.8% of the trials did not plan to include older people or those with a higher baseline risk. Most studies were randomised (67.9%), single-centre (58.3%), non-industry-funded (81.1%), to be conducted in China (47.6%), with a median duration of 184 days and a median sample size of 100 participants. Core endpoints (mortality, clinical status, and hospitalization length) were planned to be assessed in 5.2 to 13.1% of the trials. Five months later, 66 trials (11.4%) were reported as “Completed”, and only 46 (7.9%) had public results available. One hundred forty-four of 580 trials (24.8%) either had the status “Not yet recruiting” or “Suspended”, and 18 (3.1%) trials were prematurely stopped (“Terminated” or “Withdrawn”) The number of completed trials and trials with results are much lower than anticipated, considering the planned follow-up. Conclusions: Our results raise concerns about the success of the initial global research effort on COVID-19 treatment. The clinical and methodological characteristics of early COVID-19 treatment trials limit their capability to produce clear answers to critical questions in the shortest possible time.publishersversionpublishe

    Placebo response in chronic peripheral neuropathic pain trials: systematic review and meta-analysis

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    Objective: To estimate the magnitude of the placebo and nocebo responses in chronic peripheral neuropathic pain (CNP) and explore possible associations with trial characteristics. // Methods: We searched CENTRAL, MEDLINE, and Embase for randomized controlled trials (RCTs) from inception to May 2020. We included placebo-controlled RCTs of ≥8 weeks investigating first-line pharmacological interventions for CNP. Primary endpoints were the placebo response, the proportion of patients receiving placebo with pain intensity reduction (PIR) ≥30% from baseline, and the nocebo response, the proportion of patients receiving placebo experiencing adverse events (AEs). Screening, data extraction, and bias assessment (with the Cochrane risk of bias tool) were conducted by independent reviewers. We pooled data using a random-effects model. // Results: We included 50 trials, with a combined 5,693 participants allocated to placebo, conducted between 1998 and 2020. Overall, 38% of patients receiving placebo reported PIR≥30% (95% CI 34 to 42, I2=86%); 23% reported PIR≥50% (95% CI 20 to 26; I2=81%). 50% of patients receiving placebo reported AEs (95% CI 0.43 to 0.58; I2=97%); 2% reported serious AEs (95% CI 2 to 3; I2=58%). In patients receiving active interventions, the placebo response accounts for 75% of the treatment effect on PIR≥30%, and the nocebo response accounts for 75% of the AEs. Interpreted inversely, only 25% of responses and 25% of adverse events can be attributed to the intervention. Publication year positively correlated with PIR≥30% and negatively correlated with AEs. Female sex negatively correlated with AEs. // Conclusions: The placebo and nocebo responses in parallel-designed RCTs in CNP are substantial and should be considered in trial interpretation and in the design of future trials

    Historical and contemporaneous human-mediated processes left a strong genetic signature on honey bee populations from the Macaronesian archipelago of the Azores

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    In this study, honey bees fromthe Macaronesian archipelago of the Azoreswere extensively surveyed to unveil diversity patterns. A total of 638 colonies were analyzed over two time periods using mtDNA and wing geometric morphometrics. The genetic composition revealed to be heterogeneous and related to historical and contemporary human-mediated introductions. The close relationship of Azorean populations with those from northern Portugal supports historical introductions by Portuguese settlers. The African sublineage AIII prevailed on five islands, contrasting with three islands where C haplotypes were dominant. On Pico and Graciosa, C haplotypes are due to recent imports of commercial queens. On Faial, the sudden replacement of AIII by C haplotypes coincided with arrival of Varroa destructor . This study deepens the current understanding of Macaronesian honey bees, suggesting that they are variants of the Iberian honey bee with differential levels of Cderived introgression.CASM was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. Financial support was provided through the program COMPETE 2020 – POCI (Programa Operacional para a Competividade e Internacionalização) and by Portuguese funds through FCT (Fundação para a Ciência e a Tecnologia) in the framework of the project BeeHappy (POCI-01-0145-FEDER-029871).info:eu-repo/semantics/publishedVersio

    Control release of acyclovir nanocristals from electrospun nanofibers: comparison of two polymeric matrices

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    The objective of this study is to develop a novel system for cutaneous application of ACV that is capable of a controlled release of the drug overcoming the limitations of the conventional topical formulations.We are thankful to Labesfal Genericos, S.A. for kindly providing acyclovir. We also thank PARALAB for the SEM-EDS analysis and Dr. A. S. Azevedo for the X-ray analysis. This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. Marlene Lúcio acknowledges the exploratory project funded by FCT with the reference IF/00498/2012.info:eu-repo/semantics/publishedVersio

    Disturbance of Ultisol soil based on interactions between furrow openers and coulters for the no-tillage system

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    The present study evaluated the effect of different associations between coulters and fertilizer furrow openers on soil disturbance, furrow depth and width, according to forward speed. The study was conducted on a farm in Santa Maria (Brazil/RS), in soil classified as sandy loam Ultisol. The experiment consisted of 24 combinations of treatments with three replications in a 2×3×4 factorial experiment. The combinations were formed by the interaction of the factors including: two types of furrow openers (hoe and double-disc), three types of coulters (no-coulter, smooth and offset fluted) and four levels of forward speed (1.11, 1.67, 2.22 and 2.78 m/s). Soil elevation and soil disturbance area profiles were obtained with the use of a micro profilometer, and disturbance values were calculated with the aid of computer software program Auto Cad. The disturbance area was not affected by speed; it was greater when using the hoe opener, and in association with the offset fluted coulter. Speed was inversely proportional to the depth of the furrows made by the hoe opener. Furthermore, the hoe caused the greatest furrow width (0.26 m) in comparison with the double-disc (0.24 m). The use of different coulters associated with furrow openers increased this variable (0.23 m for the no-coulter condition, 0.25 m with smooth and 0.26 m with offset fluted). The use of coulters combined with furrow openers reduces soil swelling, in approximately 8% for the smooth and 20% for the offset fluted
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