582 research outputs found
Reação fenotípica de genótipos de soja a phakopsora pachyrhizi em ambientes distintos.
Estudos sobre o fungo Phakopsora pachyrhizi, causador da ferrugem-asiática da soja, tem mostrado que existe variabilidade genética entre as populações do fungo de diferentes regiões do mundo onde ele ocorre. Este trabalho teve como objetivo analisar e comparar a reação fenotípica de genótipos de soja infectados naturalmente por P. pachyrhizi em dois locais, Chapadão do Sul, MS e Londrina, PR. Para isso, 26 genótipos foram semeados a campo e avaliados quanto a severidade, a esporulação e o tipo de lesão causada pela ferrugem. Três genótipos apresentaram diferenças marcantes de reação à doença, entre os dois locais, sendo possível inferir que as populações de ferrugem que ocorreram na safra 2009/2010, nos municípios avaliados, mostraram-se geneticamente diferentes devido à reação que causaram nos genótipos testados
Analysis of acoustic feedback cancellation systems based on direct closed-loop identification
This work presents, using the least squares estimation theory, a theoretical and experimental analysis on the performance of the standard adaptive filtering algorithms when applied to acoustic feedback cancellation. Expressions for the bias and covariance matrix of the acoustic feedback path estimate provided by these algorithms are derived as a function of the signals statistics as well as derivatives of the cost function. It is demonstrated that, in general, the estimate is biased and presents a large covariance because the closed-loop nature of the system makes the cross-correlation between the loudspeaker and system input signals non-zero. Simulations are carried out to exemplify the results using speech signals, a long acoustic feedback path and the recursive least squares algorithm. The results illustrate that these algorithms converge very slowly to a solution that is not the true acoustic feedback path. The relationship between the performance of the adaptive filtering algorithms and the aforementioned cross-correlation is proven by varying the signal-to-noise ratio and the delay introduced by the forward path.info:eu-repo/semantics/publishedVersio
Rochagem: uma alternativa sustentável na remineralização de solos.
As práticas de agricultura modernas, como as que envolvem produção extensiva e a monocultura, promovem uma acentuada queda de fertilidade dos solos e geram a demanda de reposição de nutrientes através de adubos químicos. As formulações tradicionais do NPK disponibilizam macro e micronutrientes às culturas por meio de compostos solúveis e concentrados. Sua aplicação continuada em solos gera perdas inerentes à lixiviação pela água da chuva, o que acaba por contaminar os recursos hídricos, e à fixação do P solúvel em solos ricos em caolinitas, e torna-o indisponível nos ciclos seguintes de plantio.bitstream/item/204007/1/13297-2011-p.34-35.pd
Influence of antimicrobial photodynamic therapy as an adjunctive to scaling and root planing on alveolar bone loss: A systematic review and meta-analysis of animal studies.
BACKGROUND: The study aimed to evaluate the effect of antimicrobial photodynamic therapy (aPDT) as adjunctive therapy to scaling and root planing in experimental periodontitis in rats, with or without systemic involvement, by means of histometric analysis of the furcation region. METHODS: Systematic search was done using PubMed/MEDLINE, SCOPUS, EMBASE and ProQuest databases. Quantitative analysis of alveolar bone loss, with subcategories for the experimental periods studied, was performed. The analysis was performed through the mean difference (MD), with 95% confidence intervals (CIs) and according to SYRCLE guidelines. RESULTS: Nine studies were considered eligible. A statistically favorable difference was observed for the use of aPDT in all periods studied in systemically healthy animals at 7 (P < 0.00001; MD: -0.71; 95% CI: [-0.85, -0.58]; I2: 90%), 15 (P < 0.00001; MD: -0.49; 95% CI: [-0.62, -0.37]; I2: 88%), and 30 (P < 0.00001; MD: -0.53; 95% CI: [-0.65, -0.41]; I2: 80%) days postoperatively. The difference was also observed for modified animals at 7 (P < 0.00001; MD: -1.03; 95% CI: [-1.43, -0.62]; I2: 97%), 15 (P < 0.00001; MD: -1.04; 95% CI: [-1.62, -0.46]; I2: 99%), and 30 (P < 0.00001; MD: -0.88; 95% CI: [-1.37, -0.39]; I2: 97%) days postoperatively. CONCLUSION: The adjunctive use of aPDT favored the reduction of alveolar bone loss in experimental periodontitis in rats, and this result was more evident in systemically compromised rats
Periodontal disease severity in subjects with dementia: A systematic review and meta-analysis
Background and objective: Despite clinical trials and reviews attempt to assess a possible relationship between dementia and periodontal disease, no meta-analysis has been performed and this issue remains undetermined. The aim of this study is to conduct a systematic review and meta-analysis to assess severity of periodontitis in subjects with dementia.
Methods: The search was conducted in Pubmed, Embase/MEDLINE. Two independent reviewers extracted data and assessed the risk bias (Newcastle–Ottawa scale). Meta-analyses were performed using the means of probing depth (PD) and clinical attachment loss (CAL) in patients with or without dementia. The mean difference were analyzed (P ≤ 0.05).
Results: Fourteen studies were included in the systematic review. In the qualitative analysis, most studies reported higher prevalence of periodontal disease in dementia patients. The studies had low risk of bias and two meta-analyses were performed for each parameter, including or not a cross-sectional study. The meta-analyses including the cross-sectional study demonstrated significant association between dementia and periodontal disease (mean difference: PD = 1.41; CAL = 1.40, P < 0.05), however, it wasn't confirmed when the cross-sectional study was removed (1.25 mm, P < 0.22) and CAL (1.20 mm, P < 0.22).
Conclusion: Although the qualitative analysis have suggested worse periodontal conditions in dementia patients, due to different study types and the high heterogeneity among them, the meta-analysis does not support the association between dementia and severity of periodontal disease
Avaliação do estado nutricional de agroecossistemas de café orgânico no estado de Minas Gerais.
A produção de café orgânico vem se constituindo uma tendência necessária e irreversível do agronegócio brasileiro. Essa atividade tem-se destacado como uma alternativa de renda para alguns cafeicultores, devido à crescente demanda mundial por alimentos mais saudáveis. Entretanto, grande parte das técnicas propostas pela agricultura orgânica está sendo aplicada empiricamente no cultivo de café, principalmente no Estado de Minas Gerais, maior região produtora de café do Brasil. Levando-se em consideração a baixa fertilidade natural dos solos dessa região cafeeira, bem como a elevada extração de nutrientes pelo cafeeiro, objetivou-se neste trabalho identificar possíveis fatores limitantes para a produção orgânica do cafeeiro, relacionados à fertilidade do solo e ao estado nutricional das plantas. Foram realizadas avaliações da fertilidade do solo e análise das folhas em vinte e uma lavouras orgânicas representativas do Estado de Minas Gerais. As amostras de solo foram analisadas para determinação do pH, acidez potencial e dos teores de P, K, Ca, Mg, S, Al e matéria orgânica. As amostras foliares foram analisadas para determinação dos teores de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn. Com base nos padrões de interpretação para cafeeiros convencionais propostos pela literatura, estabeleceram-se as freqüências com que os caracteres analisados foram inferiores aos critérios de interpretação da fertilidade do solo e estado nutricional das plantas. A análise dos dados foi realizada por estatística descritiva. Novos trabalhos nessa nova área são necessários, visando a uma melhor interpretação da análise foliar e da fertilidade do solo, quando se trabalha com café orgânico
LASER in periodontal treatment: is it an effective treatment or science fiction?
There are several studies that evaluate the use of lasers in periodontal treatment in non-surgical or surgical therapy. However, while several studies showed clinically beneficial effects of some lasers in periodontal treatment, there are few clinical reports of additional advantages of lasers as adjunctive treatments in periodontology. The aim of this paper is to demonstrate and critically analyze the level of scientific evidence of effects of low-level lasers and high-power lasers in periodontology. A narrative review of the studies was carried out in each topic and type of laser or periodontal treatment. In nonsurgical periodontal therapy the results showed that there is an additional clinical benefit when using a diode laser (DL) associated with scaling and root planing (SRP) in patients with moderate to severe periodontitis. The Er:YAG laser seems to be the most suitable for nonsurgical periodontal therapy and promotes the same clinical effects as conventional therapy. In periodontal surgery vaporization of the gingival or mucosal tissue can be carried out with DL, CO2, Nd:YAG, Er:YAG and Er,Cr:YSGG lasers. Photobiomodulation (PBM), mediated by low-level lasers associated with non-surgical periodontal therapy, promotes additional benefits in the short term and accelerates the bone and gingival tissue repair process and also reduces postoperative symptoms of periodontal surgery. The effect of antimicrobial Photodynamic Therapy is relevant in the initial reevaluation periods. Studies have shown controversial results of the use of lasers in periodontics, and this fact may be due to the lack of standard parameters of irradiation in each clinical application
Adverse events related to ultrasound-guided regional anesthesia performed by Emergency Physicians: Systematic review protocol
The use of ultrasound-guided regional anesthesia for pain management has become increasingly prevalent in Emergency Medicine, with studies noting excellent pain control while sparing opioid use. However, the use of ultrasound-guided regional anesthesia may be hampered by concern about risks for patient harm. This systematic review protocol describes our approach to evaluate the incidence of adverse events from the use of ultrasound-guided regional anesthesia by Emergency Physicians as described in the literature. This project will also seek to document the scope of ultrasound-guided regional anesthesia applications being performed in Emergency Medicine literature, and potentially serve as a framework for future systematic reviews evaluating adverse events in Emergency Medicine
Incidência do bicho mineiro do cafeeiro em agroecossistemas convencional, organo-mineral e orgânico na região sul de Minas Gerais.
THE INFLUENCE OF DIFFERENT COMBINATIONS OF Eucalyptus saligna AND Pinus taeda VENEERS IN LVL PANELS
Investigou-se a influ\ueancia do posicionamento de l\ue2minas de
madeira de Eucalyptus saligna e Pinus taeda nas camadas de
pain\ue9is Laminated Veneer Lumber (LVL). As composi\ue7\uf5es
foram manufaturadas em seis diferentes combina\ue7\uf5es de cinco
l\ue2minas de 3,2 mm de espessura, coladas com adesivo
fenol-formalde\ueddo, resultando em tratamentos compostos de madeira
de uma mesma esp\ue9cie e outros com mistura de madeira das duas
esp\ue9cies. A avalia\ue7\ue3o dos arranjos propostos foi
realizada mediante a caracteriza\ue7\ue3o de propriedades
f\uedsicas (teor de umidade e massa espec\uedfica) e mec\ue2nicas
(m\uf3dulo de elasticidade \u2013 MOE e m\uf3dulo de ruptura
\u2013 MOR), estas verificadas em ensaios de flex\ue3o est\ue1tica
flatwise e edgewise. Os resultados obtidos indicaram que, na maior
parte das vezes, as diferentes posi\ue7\uf5es das l\ue2minas de
maior massa espec\uedfica (nas camadas externas, intermedi\ue1rias
e de miolo) influenciaram as propriedades mec\ue2nicas dos
pain\ue9is. A influ\ueancia constatada mostrou-se variada para MOE
e MOR, em especial quando comparados valores para os ensaios flatwise e
edgewise. Em determinadas posi\ue7\uf5es, nas camadas das
composi\ue7\uf5es LVL, a presen\ue7a de l\ue2minas de eucalipto
resultou em aumentos de rigidez e resist\ueancia. Contudo, os
tratamentos constitu\ueddos por l\ue2minas intercaladas de
eucalipto e pinus mostraram interessantes performances para uso
estrutural, tanto em flatwise quanto em edgewise, por apresentarem
valores de MOE e de MOR que permitem distinguilos como de 1\uaa
classe, segundo o documento t\ue9cnico norte-americano APA/EWS
PRL\u2013501 (2001).This research aimed to investigate the influence of the positioning of
Eucalyptus saligna and Pinus taeda wood veneers on layers of
laminated veneer lumber (LVL) panels. The compositions were
manufactured in six different combinations of five veneers of 3.2 mm
thickness, glued with phenol-formaldehyde, resulting in treatments
composed of wood of the same species or with a combination of two wood
types. The evaluation of the proposed arrangements was performed under
the characterization of physical properties (moisture content and
density) and mechanical properties (modulus of elasticity \u2013 MOE
and modulus of rupture \u2013 MOR) verified in flatwise and edgewise
static bending tests. The results obtained indicated that, in most
situations, the different positions of the veneers with higher density
(in the outer, intermediate and inner layers) influenced the mechanical
properties of the panels. The influence detected was varied for MOE and
MOR, especially when comparing the flatwise and edgewise test values.
In certain positions, on the layers of the LVL compositions, the
presence of eucalypt veneers resulted in stiffness and strength
increases. However, the treatments formed by interposed veneers of
eucalypt and pine demonstrated interesting performances for structural
use, in either flatwise or edgewise position, once they present values
of MOE and MOR that allow to distinguish them as 1st class, according
to the North American standard APA/EWS PRL\u2013501 (2001)
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