Análise de nitrogênio total em amostras de tecido vegetal pelos métodos de Dumas e Kjeldahl.

O objetivo deste trabalho é comparar os resultados obtidos pelos dois métodos utilizados para análise de nitrogênio total (Nt), que são os métodos de Kjeldhal e Dumas, em algumas amostras de tecido vegetal e grãos normalmente analisadas na rotina do laboratório

Orientation dynamics of weakly Brownian particles in periodic viscous flows

Evolution equations for the orientation distribution of axisymmetric particles in periodic flows are derived in the regime of small but non-zero Brownian rotations. The equations are based on a multiple time scale approach that allows fast computation of the relaxation processes leading to statistical equilibrium. The approach has been applied to the calculation of the effective viscosity of a thin disk suspension in gravity waves.Comment: 16 pages, 7 eps figures include

The scenario of two-dimensional instabilities of the cylinder wake under EHD forcing: A linear stability analysis

We propose to study the stability properties of an air flow wake forced by a dielectric barrier discharge (DBD) actuator, which is a type of electrohydrodynamic (EHD) actuator. These actuators add momentum to the flow around a cylinder in regions close to the wall and, in our case, are symmetrically disposed near the boundary layer separation point. Since the forcing frequencies, typical of DBD, are much higher than the natural shedding frequency of the flow, we will be considering the forcing actuation as stationary. In the first part, the flow around a circular cylinder modified by EHD actuators will be experimentally studied by means of particle image velocimetry (PIV). In the second part, the EHD actuators have been numerically implemented as a boundary condition on the cylinder surface. Using this boundary condition, the computationally obtained base flow is then compared with the experimental one in order to relate the control parameters from both methodologies. After validating the obtained agreement, we study the Hopf bifurcation that appears once the flow starts the vortex shedding through experimental and computational approaches. For the base flow derived from experimentally obtained snapshots, we monitor the evolution of the velocity amplitude oscillations. As to the computationally obtained base flow, its stability is analyzed by solving a global eigenvalue problem obtained from the linearized Navier–Stokes equations. Finally, the critical parameters obtained from both approaches are compared

Advances in Plant Virus Evolution: Translating Evolutionary Insights into Better Disease Management

Recent studies in plant virus evolution are revealing that genetic structure and behavior of virus and viroid populations can explain important pathogenic properties of these agents, such as host resistance breakdown, disease severity, and host shifting, among others. Genetic variation is essential for the survival of organisms. The exploration of how these subcellular parasites generate and maintain a certain frequency of mutations at the intra- and inter-host levels is revealing novel molecular virus–plant interactions. They emphasize the role of host environment in the dynamic genetic composition of virus populations. Functional genomics has identified host factors that are transcriptionally altered after virus infections. The analyses of these data by means of systems biology approaches are uncovering critical plant genes specifically targeted by viruses during host adaptation. Also, a next-generation resequencing approach of a whole virus genome is opening new avenues to study virus recombination and the relationships between intra-host virus composition and pathogenesis. Altogether, the analyzed data indicate that systematic disruption of some specific parameters of evolving virus populations could lead to more efficient ways of disease prevention, eradication, or tolerable virus–plant coexistence.SD was supported by the NJ Agricultural Experiment Station. SFE was supported by grants from the Spanish Ministerio de Ciencia e Innovación (BFU2009-06993) and Generalitat Valenciana (PROMETEO2010/019). Work on CTV was supported by funding from USDA grants 2003-34399-13764 and 2005-34399-16070 to ZX. Work on BNYVV was funded by The Minnesota-North Dakota Research and Education Board, and The Beet Sugar Development Foundation. RAL thanks Ramon L. Jordan (USDA-ARS, MPPL), Rayapati A. Naidu(Washington State University), and Scott Adkins (USDA ARS USHRL) for their logistic support in the realization of the originating symposium.Peer reviewe

Crescimento vegetativo de novos porta-enxertos híbridos de citros.

Os frutos cítricos representam 23% da produção mundial de frutas e há décadas o Brasil ocupa posição de destaque na citricultura internacional, com um parque citrícola de 802,5 mil ha. Esta posição é vulnerável, devido ao predomínio do limoeiro ?Cravo? (Citrus limonia Osbeck) como único porta-enxerto na sustentação dos pomares. Nesse contexto, a Embrapa Mandioca e Fruticultura vem executando um programa de hibridações visando criar novas variedades, principalmente porta-enxertos, adaptadas a diferentes regiões geográficas do País.PDF. 108_11

Superpulsed low-level laser therapy protects skeletal muscle of mdx mice against damage, inflammation and morphological changes delaying dystrophy progression.

Aim: To evaluate the effects of preventive treatment with low-level laser therapy (LLLT) on progression of dystrophy in mdx mice. Methods: Ten animals were randomly divided into 2 experimental groups treated with superpulsed LLLT (904 nm, 15 mW, 700 Hz, 1 J) or placebo-LLLT at one point overlying the tibialis anterior muscle (bilaterally) 5 times per week for 14 weeks (from 6th to 20th week of age). Morphological changes, creatine kinase (CK) activity and mRNA gene expression were assessed in animals at 20th week of age. Results: Animals treated with LLLT showed very few morphological changes in skeletal muscle, with less atrophy and fibrosis than animals treated with placebo-LLLT. CK was significantly lower (p = 0.0203) in animals treated with LLLT (864.70 U.l−1, SEM 226.10) than placebo (1708.00 U.l−1, SEM 184.60). mRNA gene expression of inflammatory markers was significantly decreased by treatment with LLLT (p<0.05): TNF-α (placebo-control = 0.51 µg/µl [SEM 0.12], - LLLT = 0.048 µg/µl [SEM 0.01]), IL-1β (placebo-control = 2.292 µg/µl [SEM 0.74], - LLLT = 0.12 µg/µl [SEM 0.03]), IL-6 (placebo-control = 3.946 µg/µl [SEM 0.98], - LLLT = 0.854 µg/µl [SEM 0.33]), IL-10 (placebo-control = 1.116 µg/µl [SEM 0.22], - LLLT = 0.352 µg/µl [SEM 0.15]), and COX-2 (placebo-control = 4.984 µg/µl [SEM 1.18], LLLT = 1.470 µg/µl [SEM 0.73]). Conclusion: Irradiation of superpulsed LLLT on successive days five times per week for 14 weeks decreased morphological changes, skeletal muscle damage and inflammation in mdx mice. This indicates that LLLT has potential to decrease progression of Duchenne muscular dystrophy

An assessment of the health belief model (HBM) properties as predictors of COVID-19 preventive behaviour

Background: Public participation in preventive efforts is crucial in preventing infection and reducing mortality attributed to infectious diseases. The health belief model (HBM) suggests that individuals will likely participate in these efforts when experiencing a personal threat or risk, but only if the benefits of acting outweigh the risk or perceived barriers. Methods: The current study explores the properties of the HBM as predictors of the public’s compliance with COVID-19 preventive behaviour. Quantitative data on HBM properties, COVID-19 preventive behaviour, socioeconomic (SES) and demographic characteristics were collected from a sample of 674 adults in Hamburg, Germany. Binary logistic regression was computed to examine the effect of the properties of HBM on COVID-19 vaccination. Multiple linear regression was calculated to investigate the impacts of HBM properties on the likelihood of participants’ face mask usage as a protective measure against COVID-19 infection. Results: The logistic regression model was statistically significant, X2(13) = 149.096, p <.001. The specificity and sensitivity for the model is 58.1% and 99.4%, respectively. Similarly, the multiple regression model results showed a good fit for the data. F (13, 650) = 17.093, p <.001, and adjusted R2=.240, suggesting that HBM properties predict face mask usage. Conclusion: This study’s findings provide robust evidence to recommend that the concerned public health professionals consider individuals’ health beliefs when designing an effective COVID-19 preventive programme. Public health messaging should consider highlighting the benefits of preventive actions and the potential lethality of COVID-19 to evoke an individual’s appropriate concern

Otimização da concentração de misturas de herbicidas considerando a resistência de plantas daninhas.

I CMAC Sudeste

An Odorant Receptor from the Southern House Mosquito Culex pipiens quinquefasciatus Sensitive to Oviposition Attractants

Insect odorant receptors (ORs) are heteromers comprised of highly variable odorant-binding subunits associated with one conserved co-receptor. They are potential molecular targets for the development of novel mosquito attractants and repellents. ORs have been identified in the malaria mosquito, Anopheles gambiae, and in the yellow fever mosquito, Aedes aegypti. However, they are still unknown in the Southern house mosquito, Culex quinquefasciatus, which transmits pathogens that cause human diseases throughout the world, including West Nile Virus in the United States.We have employed a combination of bioinformatics, molecular cloning and electrophysiology approaches to identify and characterize the response profile of an OR in Cx. quinquefasciatus. First, we have unveiled a large multigenic family of one-hundred-fifty-eight putative ORs in this species, including a subgroup of conserved ORs in three mosquito species. Using the Xenopus oocytes expression system, we have determined the response profile of CquiOR2, an antennae-specific OR, which shares high identity with putative orthologs in Anopheles gambiae (AgamOR2) and Aedes aegypti (AaegOR2).We show that CquiOR2 is highly sensitive to indole, an oviposition attractant for Cx. quinquefasciatus. The response profile of CquiOR2 expressed in Xenopus oocytes resembles that of an olfactory receptor neuron housed in the antennal short blunt-tipped sensilla (A2) of Cx. quinquefasciatus, which are natural detectors for oviposition attractants. This first Culex OR de-orphanized is, therefore, a potential molecular target for screening oviposition attractants