207 research outputs found

    A cultura do urucum em 1994.

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    Microstructure identification via detrended fluctuation analysis of ultrasound signals

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    We describe an algorithm for simulating ultrasound propagation in random one-dimensional media, mimicking different microstructures by choosing physical properties such as domain sizes and mass densities from probability distributions. By combining a detrended fluctuation analysis (DFA) of the simulated ultrasound signals with tools from the pattern-recognition literature, we build a Gaussian classifier which is able to associate each ultrasound signal with its corresponding microstructure with a very high success rate. Furthermore, we also show that DFA data can be used to train a multilayer perceptron which estimates numerical values of physical properties associated with distinct microstructures.Comment: Submitted to Phys. Rev.

    Sobrevivência de Pseudomonas solanacearum Raça 2 em solos de terra-firme do Estado do Amazonas.

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    Made available in DSpace on 2019-11-07T18:08:42Z (GMT). No. of bitstreams: 1 FitoBRa42273.pdf: 4499760 bytes, checksum: 87c4aedf5136f6c0442944a667ff0f1e (MD5) Previous issue date: 1993bitstream/item/195692/1/FitoBRa-422-73.pd

    Effects of COVID-19 pandemic on glaucoma appointment scheduling in a tertiary hospital in London, UK

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    PURPOSE: To investigate the impact of the delay in patient appointments caused by the COVID-19 pandemic and the triage system on the glaucomatous disease of patients in a London tertiary hospita METHODS: Observational retrospective study that randomly selected 200 glaucoma patients with more than 3 months of unintended delay for their post-COVID visit and other inclusion and exclusion criteria. Demographic information, clinical data, number of drugs, best-corrected visual acuity (BCVA), intraocular pressure (IOP), visual field (VF) mean deviation (MD), and global peripapillary retinal nerve fibre layer (pRNFL) thickness were obtained from the pre- and post-COVID visit. At the post-COVID visit, the clinical outcomes subjective clinical concern and change of treatment or need for surgery were also annotated. The variables were stratified by glaucoma severity (according to the MD into early, moderate and advanced) and by delay time (more and less than 12 months) and analysed using SPSS. RESULTS: We included 121 eyes (from 71 patients). The median patient age was 74 years (interquartile range -IQR- 15), 54% were males and 52% Caucasians. Different glaucoma types and all glaucoma severities were included. When data was stratified for glaucoma severity, at the pre-COVID visit, significant differences in BCVA, CCT and IOP were observed and there were significantly higher values in the early glaucoma group. The median follow-up delay was 11 months (IQR 8), did not differ between the glaucoma severity groups and did not correlate to the glaucoma severity. At the post-COVID visit, significant differences in BCVA, IOP, and Global pRNFL thickness were observed between the glaucoma severity groups, as lower BCVA and higher IOP and pRNFL thickness were observed in the early glaucoma group. At the post-COVID visit there was cause for concern in 40 eyes: 5 were followed more closely, 22 had a change of treatment and 13 were booked for surgery (3 for cataract and 10 for glaucoma surgery). However, the number of eyes with causes for concern were similar between the glaucoma severity groups and there was no correlation between these clinical outcomes and the delay of the post-COVID visit. The number of topical hypotensive medications increased significantly after the post-COVID visit, higher number of medications were observed in the advanced glaucoma group. When differences of IOP, MD and pRNFL thickness between the pre and post-COVID visit, only the MD difference was significantly different between the glaucoma severity groups because it was higher in the severe group. When data was stratified for delay longer or shorter than 12 months, no differences were observed between the groups except at the pre-COVID visit, when the numbers of patients with MD deviation >−6 dB had longer delay time. When differences in IOP, MD and RNFL thickness were calculated, only the pRNFL thickness showed significant differences between the delay groups, because it was higher in the longer delay group. Finally, when paired analysis of the variables at the pre- and post-COVID visits, stratified by glaucoma severity and delay were conducted, although there were no significant differences in IOP in any group, the BCVA decreased significantly in the overall group and in the longer delay groups, the number of hypotensive drugs increased significantly overall and in the moderate and advanced glaucoma, the MD of the VF worsened significantly in the overall group and in the early glaucoma and longer delay groups and the pRNFL thickness decreased significantly in all groups. CONCLUSIONS: We document that delayed care impacts negatively on the glaucomatous disease of our patients because at the post-COVID visit there were reasons for clinical concern in a third of eyes that resulted in change of treatment or surgery. However, these clinical consequences were not related to IOP, glaucoma severity or delay time and reflect that the triage methods implemented worked adequately. The most sensitive parameter to indicate progression in our sample was the pRNFL thickness

    MicroShunt versus trabeculectomy for surgical management of glaucoma: a retrospective analysis

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    This case-control study aims to compare the efficacy, safety, and postoperative burden of MicroShunt versus trabeculectomy. The first consecutive cohort of MicroShunt procedures (n = 101) was matched to recent historical trabeculectomy procedures (n = 101) at two London hospital trusts. Primary endpoints included changes in intraocular pressure (IOP) and glaucoma medications. Secondary outcome measures included changes in retinal nerve fibre layer (RNFL) thickness, rates of complications, further theatre interventions, and the number of postoperative visits. From the baseline to Month-18, the median [interquartile range] IOP decreased from 22 [17–29] mmHg (on 4 [3–4] medications) to 15 [10–17] mmHg (on 0 [0–2] medications) and from 20 [16–28] mmHg (on 4 [3–4] medications) to 11 [10–13] mmHg (on 0 [0–0] medications) in the MicroShunt and trabeculectomy groups, respectively. IOP from Month-3 was significantly higher in the MicroShunt group (p = 0.006), with an increased number of medications from Month-12 (p = 0.024). There were greater RNFL thicknesses from Month-6 in the MicroShunt group (p = 0.005). The rates of complications were similar (p = 0.060) but with fewer interventions (p = 0.031) and postoperative visits (p = 0.001) in the MicroShunt group. Therefore, MicroShunt has inferior efficacy to trabeculectomy in lowering IOP and medications but provides a better safety profile and postoperative burden and may delay RNFL loss

    BRS - Prata Caprichosa.

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    BRS - Prata Caprichosa: cultivar de bananeira resistente à sigatoka-negra. Características fitotécnicas da BRS - Prata Caprichosa. Reação da BRS - Prata Caprichosa a doenças e pragas.bitstream/item/126443/1/Folder-Prata-Caprichosa.pd

    Real-time imaging of single neuronal cell apoptosis in patients with glaucoma

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    Retinal cell apoptosis occurs in many ocular neurodegenerative conditions including glaucoma—the major cause of irreversible blindness worldwide. Using a new imaging technique that we have called DARC (detection of apoptosing retinal cells), which until now has only been demonstrated in animal models, we assessed if annexin 5 labelled with fluorescent dye DY-776 (ANX776) could be used safely in humans to identify retinal cell apoptosis. Eight patients with glaucomatous neurodegeneration and evidence of progressive disease, and eight healthy subjects were randomly assigned to intravenous ANX776 doses of 0.1, 0.2, 0.4 and 0.5 mg in an open-label, phase 1 clinical trial. In addition to assessing the safety, tolerability and pharmacokinetics of ANX776, the study aimed to explore whether DARC could successfully visualize individual retinal cell apoptosis in vivo in humans, with the DARC count defined as the total number of unique ANX776-labelled spots. DARC enabled retinal cell apoptosis to be identified in the human retina using ANX776. Single ANX776-labelled cells were visualized in a dose-dependent pattern (P5 0.001) up to 6 h after injection. The DARC count was significantly higher (2.37-fold, 95% confidence interval: 1.4–4.03, P = 0.003) in glaucoma patients compared to healthy controls, and was significantly (P = 0.045) greater in patients who later showed increasing rates of disease progression, based on either optic disc, retinal nerve fibre layer or visual field parameters. Additionally, the DARC count significantly correlated with decreased central corneal thickness (Spearman’s R = 0.68, P = 0.006) and increased cup-disc ratios (Spearman’s R = 0.47, P = 0.038) in glaucoma patients and with increased age (Spearman’s R = 0.77, P = 0.001) in healthy controls. Finally, ANX776 was found to be safe and well-tolerated with no serious adverse events, and a short half-life (10–36 min). This proof-of-concept study demonstrates that retinal cell apoptosis can be identified in the human retina with increased levels of activity in glaucomatous neurodegenerative disease. To our knowledge, this is the first time individual neuronal apoptosis has been visualized in vivo in humans and is the first demonstration of detection of individual apoptotic cells in a neurodegenerative disease. Furthermore, our results suggest the level of apoptosis (‘DARC count’) is predictive of disease activity, indicating the potential of DARC as a surrogate marker. Although further trials are clearly needed, this study validates experimental findings supporting the use of DARC as a method of detection and monitoring of patients with glaucomatous neurodegeneration, where retinal ganglion cell apoptosis is an established process and where there is a real need for tools to non-invasively assess treatment efficacy

    Agrossistemas alternativos para produtores de agricultura migratória em Presidente Figueiredo-AM.

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    Com o objetivo de se estudar alternativas de uso da terra para pequenos produtores de agricultura migratoria no municipio de Presidente Figueiredo (AM), dois modelos de sistemas agroflorestais foram implantados em tres propriedades rurais do municipio. Os sistemas foram constituidos por sistemas perenes (cupuacu, pupunha, inga) e semiperene (banana). Nos espacos disponiveis foram testados arranjos sequenciais de componentes anuais: Sistema I - mandioca, caupi + mandioca; Sistema II - arroz, caupi + mandioca. Os sistemas, no primeiro ano, foram testados com: 1) adubacao NPK + M. O.; 2) sem adubacao; e 3) com duas leguminosas (Arachis hypogaea e Stizolobium aterrimum) de cobertura de solo. No segundo ano, foram aplicados, nos tratamentos sem adubacao, uma dose de P. Analises do solo indicaram valores altos para aluminio trocavel e baixos para carbono, caracterizando a baixa fertilidade natural do solo. A biomassa da parte aerea vegetal da copoeira de dois anos (cerca de 4t/ha de materia seca) promoveu, apos a queima, aumento significativo nos teores de nutrientes no solo. Os resultadores evidenciaram o efeito da adubacao no crescimento e producao das plantas, no primeiro ano. A maior producao total obtida por area (58% de mandioca, 78% de caupi e 100% de banana), durante o periodo, foi conseguida por tratamento com adubacao, superando os demais tratamento em quase cinco vezes os valores da receita, o que leva a acreditar serem economicamente viaveis os sistemas estudados, com tendencia de sustentabilidade a longo prazo.bitstream/CPAA-2009-09/2313/1/BP-3.pd

    Avaliação da capacidade preditiva da circunferência da cintura para obesidade global e hipertensão arterial em mulheres residentes na Região Metropolitana de Belo Horizonte, Brasil

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    Avaliou-se a capacidade que a Circunferência da Cintura (CC) tem em identificar valores de IMC ≥25 (sobrepeso) e ≥30 (obesidade) a partir de níveis de ação recomendados internacionalmente. Setecentas e noventa e uma mulheres entre 15-59 anos foram recrutadas. Foram calculadas a sensibilidade e a especificidade no diagnóstico de sobrepeso e obesidade e a sensibilidade e especificidade na predição da hipertensão, a partir de valores de CC. As associações foram testadas por análise de regressão linear e regressão logística controlando para o efeito de fatores de confusão. A CC ≥80 e ≥88cm discriminou corretamente 89,8% de mulheres com IMC ≥25 e 88,5% com IMC ≥30. A obesidade abdominal (CC ≥88cm) esteve associada significativamente com a hipertensão na análise multivariada (OR = 2,88, IC 95%: 1,77-4,67). A hipertensão foi identificada com sensibilidade de 63,8 e 42,8% e especificidade de 68,0 e 83,3% para CC ≥80 e ≥88, respectivamente. A obesidade abdominal nos pontos de corte propostos pode discriminar adequadamente indivíduos em risco de se tornarem obesos, no entanto, apresenta um poder apenas moderado para discriminar indivíduos com níveis pressóricos altos. _______________________________________________________________________________ ABSTRACTThis study examined the capacity of waist circumference (WC) to identify subjects with overweight (BMI ≥25) and obesity (BMI ≥30), in agreement with internationally recommended levels of action. Data were obtained from 791 women, 15-59 years old. After identifying overweight and obesity according to WC values, sensitivity and specificity were calculated to verify whether WC could be a good risk predictor for hypertension. Associations were tested by linear regression and logistic regression, controlling for confounding.WC cut-off points of 80cm and 88cm correctly identified 89.8% and 88.5% of women with overweight and obesity, respectively. Abdominal obesity (WC ≥88cm) was statistically associated with hypertension in the multivariate analysis (OR = 2.88; 95% CI: 1.77-4.67). Hypertension was identified with a sensitivity of 63.8% and 42.8%, and with a specificity of 68.0% and 83.3%, for WC ≥80 and ≥88, respectively. The proposed cut-off points for abdominal obesity can potentially distinguish individuals at risk for future obesity, but has only moderate power to predict individuals with high blood pressure

    Associação entre beneficiamento e tratamento com inseticidas tem impacto na qualidade dos grãos de milho durante a armazenagem?

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    O presente trabalho teve como objetivo avaliar o impacto do beneficiamento por meio de mesa densimétrica em combinação com a aplicação de inseticidas na qualidade final dos grãos de milho durante a armazenagem.Evento online
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